Hard Disk Repairing

I am using 10.3.9 and have a question. I used to occasionally use Disk First Aid to check if there were problems with my Hard Disk. When I tried to do this process I was told to insert the start up disk and boot from it and then I could verify or repair my hard disk.
1. Is this necessary
2. How do I boot from the OS X CD
3. I use ONYX once in a while to "clean" things up
Is there anything else I can do on a regular basis to be sure Mac is operating at full potential?
Any assistance would be appreciated
Thanks
John

guard:
I do not personally use Onyx, although I use other maintenance tools, many of which are linked in the article linked by ali brown.
To repond to your question specifically, Disk Utility has a number of functions, one of which is Repair Disk. The procedure essentially examines the directories on your formatted volumes, and, in some cases, repairs minor directory problems. When there are major directory issues, DU advises that there are errors which it cannot repair, in which case you will need to use a utility like Tech Tool Pro, Disk Warrior, or DriveGenius. As far as I know, Onyx does not do directory work. I believe that it does do Unix Maintenance, which Disk Utility does not do, and it duplicates the DU function of Repairing Disk Permissions. In other words, while one of the utilities just linked may replace the Repair Disk function in directory maintenance and repair, Onyx, from what I have read, does not. Directory maintenance and Repair is vital function since the directories are the electronic structures in the formatted volume which control how the volume manages and stores data. Damaged or corrupted directories can cause loss of data or a Hard Disk Drive crash. For more information on this subject see Dr. Smoke's FAQ The Repair functions of Disk Utility: what's it all about?.
Please do post back with further questions or comments.
Cheers.
cornelius

Similar Messages

Hard Disk Repair Help!

Good evening,
Just wondering if you guys can give me any help with regards to my Mid 2010 Mac Mini running Mountain Lion.
I only use the computer for internet browsing and iTunes, I've upgraded the RAM to 8GB myself which was straight forward.
Yesterday I get home from work and the Mac is turned off (I usually leave it on Stand-By). Upon turning it on by the button on the back I get the Apple Logo and the rotating circle, followed by this screen;
[IMG]http://i117.photobucket.com/albums/o78/Jonny2modified/6E058BF7-C5CC-4725-BB6E-64 D53168DAD8-11438-00000B443DCDE4DC_zps4a055f0a.jpg[/IMG]
If I click on Disk Utility I've got these options on the left;
[img]http://i117.photobucket.com/albums/o78/Jonny2modified/B1377C74-71DB-45B0-B700-11 77B06FC73D-11438-00000B4442D9F747_zps5208f360.jpg[/img]
I've a 160GB external hard drive which has stuff on it now but could transfer that stuff over to a very old and slow laptop if I need the extra space for backing up.
Verify Disk on the top drive gives me this, which looks fine?;
[IMG]http://i117.photobucket.com/albums/o78/Jonny2modified/777713AF-708F-4723-B947-2B 9337725A74-11438-00000B444825DEFF_zps957f56f9.jpg[/IMG]
But Disk Repair on the greyed out drive gives me this;
[IMG]http://i117.photobucket.com/albums/o78/Jonny2modified/5A6FC9F4-79E9-44DB-ACF3-96 44F9631AEB-11438-00000B444DBBA0CE_zps46e5ea78.jpg[/IMG]
Which doesn't sound good?
The bad bit.. I've not backed up anything since I got the computer, I've got pictures/music on my computer I'd like to keep if possible.. But I don't know anything about backing things up, or how I'd go about it. Sounds pretty terminal from that pop-up message from Apple!
I've got installation disks if I need them.
So you helpful people - What do I need to do first?
Thanks in advance!
(Apologies about the bad pictures, thought it'd be better than nothing though!)

Thanks so far, Viking.
Tried to do the Shift or S key on boot up after/on the chime but nothing.
Will try a wired keyboard tomorrow, will any USB keyboard work to you know? Can borrow one from work if so..
EDIT;
I appear to have got it into Single User Mode. Tried the fsck command, this is what I got back from that;
http://i117.photobucket.com/albums/o78/Jonny2modified/19CDDA7A-43CF-4F3C-A4B7-22 BAA013BB53-12042-00000B863A4EDB71_zps64426d37.jpg
Still started up in Disk Utility..
If I try and install Lion again I get this;
http://i117.photobucket.com/albums/o78/Jonny2modified/C2691425-5AA3-43B7-B354-58 F1F9AA199B-12042-00000B863E72ED34_zpsc5118a5e.jpg
So, I guess it's dead?

Unsuccessful install - HD Disk Repair - what's the safe/smart way?

Thank you in advance.
I'm trying to update my OS from Leopard to Snow Leopard, but the install is unsuccessful. I have an intel based iMac on which I initially used Tiger and then upgraded to Leopard without any trouble. In the Snow Leopard installation instructions, I read that I should try a few hard drive maintenance measures, but none of those have led to a successful update. Upon trying to verify the disk, Disk Utility reports that the disk does need repair, which is the next troubleshooting step according to the Snow Leopard install guide. Apparently, I can only do so by booting up the computer off an OS installation disc. Naturally, this is a bit disconcerting because I am under the impression that when I repair the disk, it will wipe my hard drive clean; thus, I will have to restore all of my hard drive from a backup or some sort of copy of my iMac hard drive. Unfortunately, I do not fully understand what actually occurs in a hard disk repair and what the potential ramifications are nor do I fully understand what a hard drive restore or re-copying it back to my computer does.
My goal is to update the OS to Snow Leopard so that CS4 is compatible with my computer. Also, I have had trouble using Canon codecs in Final Cut Pro; in fact, I can't even transcode them using the log and transfer option, and I read that an OS update to Snow Leopard may fix the issue. Of course, my ideal scenario is to update the OS while maintaining or easily restoring/copying my iMac Hard Drive volume back to my computer with the updated OS, without having to reinstall apps/software or even redoing all of my preferences or the setup, settings and shortcuts on my desktop and dock. Is this possible? Do you have any suggestions for a better way to go about all of this?
Here are some of my concerns more specifically:
Ordinarily, I try to backup my iMac Hard Drive with QRecall to an external hard drive regularly, but I have never actually had to restore any of the content, thankfully. For the purposes of what I am trying to do, would it be more sensible to just do a drag and drop copy of the iMac Hard Drive volume to an external and then back to the iMac after repairing the iMac hard drive disk and updating the OS or is it smarter to restore from the QRecall archive?
Assuming the hard drive disk repair solves the problem, when should I update the OS, before or after restoring my iMac hard drive? Or is the OS update something that I will do during the iMac hard drive disk repair?
Maybe this is a stupid question, but when I restore or copy (not sure of proper terminology) my current iMac Hard Drive Volume back to my computer, is the old OS not a part of that? Is it possible that I'd update the OS, then restore or copy the hard drive volume back to the computer, and then it would revert back to the older OS Leopard?
Again, thank you very much.

I am under the impression that when I repair the disk, it will wipe my hard drive clean;
That is an incorrect assumption. A disk repair will not erase the hard drive. See:
http://support.apple.com/kb/HT1782
It may, however, be the case that Disk Utility cannot repair the drive catalog. If that occurs, you can try a third-party disk repair tool - Alsoft's Disk Warrior is the one most often recommended - and if that fails then you will have to erase or, if erasing fails, replace the hard drive.
My goal is to update the OS to Snow Leopard so that CS4 is compatible with my computer.
Snow Leopard is not necessary for CS4 compatibility. CS4 predates Snow Leopard by quite a while and is and always has been compatible with 10.5 Leopard. CS5 is necessary for full Snow Leopard support.
would it be more sensible to just do a drag and drop copy of the iMac Hard Drive volume to an external
You cannot do a drag-and-drop backup of your hard drive. There are many hidden files and linkages that would not be copied.
when I restore or copy (not sure of proper terminology) my current iMac Hard Drive Volume back to my computer, is the old OS not a part of that?
Your backup has whatever OS version was on your computer when you made the backup. So if you restore that backup (assuming you backed up the entire drive and restore that same entire drive), you'll be going back to that version of Mac OS X.
I'm complete unclear on when you've made a backup and what got backed up, so without more information I can't say the steps I would take in your situation. Post back with details on your backup and we'll go from there.
Regards.

How I installed Mountain Lion on Un-repairable Hard Disk.

My Recommendations for Avoiding Trouble, Avoiding Risk, and Saving Time.
1) Make a boot clone first!!!
      http://www.bombich.com/
http://www.shirt-pocket.com/SuperDuper/SuperDuperDescription.html
2) Fix and repair your hard disk with Disk Utility and fsck_hfs before installing Mountain Lion!
    (Otherwise the installer will write-lock the disk preventing repair.)
Mountain Lion Aborted Installation—Claimed Hard Disk Failed, Couldn't be Repaired, and Should be Replaced
I have a 2011 MacBook Pro. Installation of Mountain Lion aborted claiming the hard disk could not be repaired by Disk Utility, should be backed up immediately, and replaced. It didn't make sense that the drive was booting up the computer for installation, but needed replacing. I removed the drive, put it in an external enclosure, and backed up the drive using a working Mac Mini, and Carbon Copy Cloner.
Hard Disk Was Write-Locked—Not Failing
Booting in Single User mode (hold command and S keys down while bootup is proceeding). I then typed in the fsck command given after Single User bootup. It informed me the drive was write-locked and read only. Now things were starting to make sense. Disk Utility couldn't repair the drive because it was write-locked! Maybe it could have been unlocked by the "chflags nouchg /Volumes/volume" or "chflags noschg /Volumes/volume" commands (http://hints.macworld.com/article.php?story=20031017061722471), but I didn't try it. Unlocking the drive is really worht a try because it could save hours of coppying through a slow USB interface.
I formatted my laptop drive after copying it to another large external drive. Then I used Carbon Copy Cloner to clone Snow Leopard from my Mac Mini to my freshly formatted original laptop drive. I unsellected the "Users" folder so I would only get the operating system—saving lots of hours copying data I don't need. Then I put the drive back in my laptop, and it booted with Snow Leopard. Checked the volume with Disk Utility and was informed the drive is fine. I removed the drive and connected it externally to my Mac Mini and ran fsck_hsf a few times in the terminal, which showed problems were found and fixed.
sudo fsck_hfs -fy /dev/rdisk1s2
Password:
** /dev/rdisk1s2 (NO WRITE)
   Executing fsck_hfs (version diskdev_cmds-491.6~3).
** Verifying volume when it is mounted with write access.
** Checking Journaled HFS Plus volume.
** Checking extents overflow file.
** Checking catalog file.
** Checking multi-linked files.
** Checking catalog hierarchy.
** Checking extended attributes file.
** Checking volume bitmap.
   Volume bitmap needs minor repair for under-allocation
** Checking volume information.
   Invalid volume file count
   (It should be 550614 instead of 550591)
   Invalid volume free block count
   (It should be 175459733 instead of 175460263)
** The volume MacBookPro HD was found corrupt and needs to be repaired.
3) sudo fsck_hfs /dev/rdisk1s2
Password:
** /dev/rdisk1s2 (NO WRITE)
   Executing fsck_hfs (version diskdev_cmds-491.6~3).
** Verifying volume when it is mounted with write access.
** Checking Journaled HFS Plus volume.
fsck_hfs: Volume is journaled. No checking performed.
fsck_hfs: Use the -f option to force checking.
[karl_ihrig] 4) sudo fsck_hfs -f /dev/rdisk1s2
** /dev/rdisk1s2 (NO WRITE)
   Executing fsck_hfs (version diskdev_cmds-491.6~3).
** Verifying volume when it is mounted with write access.
** Checking Journaled HFS Plus volume.
** Checking extents overflow file.
** Checking catalog file.
** Checking multi-linked files.
** Checking catalog hierarchy.
** Checking extended attributes file.
** Checking volume bitmap.
** Checking volume information.
** The volume MacBookPro HD appears to be OK.
5) sudo fsck_hfs -fy /dev/rdisk1s2
** /dev/rdisk1s2 (NO WRITE)
   Executing fsck_hfs (version diskdev_cmds-491.6~3).
** Verifying volume when it is mounted with write access.
** Checking Journaled HFS Plus volume.
** Checking extents overflow file.
** Checking catalog file.
** Checking multi-linked files.
** Checking catalog hierarchy.
** Checking extended attributes file.
** Checking volume bitmap.
** Checking volume information.
** The volume MacBookPro HD appears to be OK.
6) sudo fsck_hfs -fy /dev/disk1s2
** /dev/rdisk1s2 (NO WRITE)
   Executing fsck_hfs (version diskdev_cmds-491.6~3).
** Verifying volume when it is mounted with write access.
** Checking Journaled HFS Plus volume.
** Checking extents overflow file.
** Checking catalog file.
** Checking multi-linked files.
** Checking catalog hierarchy.
** Checking extended attributes file.
** Checking volume bitmap.
** Checking volume information.
** The volume MacBookPro HD appears to be OK.
I put the drive back in the laptop and repeated the fsck commands after a Single User boot. (Omited the sudo commands and used /dev/disk0s2.)
Downloaded and Successfully Installed Mountain Lion on "Unreparable" Drive
I downloaded the Mountan Lion installation application to my laptop, ran it, and had a smooth install.
More Trouble Migraiting My Applications and Directory
I expect to use up more time changing my computer name, migrating applications and rsyncing my User Directory. I will post how I achieve this.
I Hope People Avoid Trouble and Problems are Solved
I hope everyone will avoid trouble by making boot clone of their whole disk before attempting an install of ML and repairing their disk with Disk Utility and fsck before ML installer prevents it with a write-lock. Please see the first section.
I hope this solves other peoples problems with 'unreparable' disks. I believe this proves disks are repairable when ML says otherwise.
Good luck everyone!

troca, you certainly helped dtigerbme! Isn't that encouraging?
I recommend you copy your drive as soon as possible. I really don't think the drive is bad, but you may have to format it and copy back to it. Hopefully not. Clone or backup the drive before trying this recipe. Any time you have errors on a drive, back it up. A failing drive has lmited life. However, I don't think these drives are really failing, but that is my opinion and I break a lot of things.
Let's try this recepie for you:
Start in Single User Mode. Power on while holding the Command + S keys.
At the prompt, type "fsck_hfs -fy" or "fsck -fy" and hit return.
Do it again.
Enter the command "reboot".
Just googled "volume count disk utility" and got the same recipe to fix it.
http://counterjumper.com/post/19265700171/how-to-fix-invalid-volume-free-block-c ount-error-in
So my recipe is to try to fix the drive without taking it out of the computer, which requires you can boot it up.
troca it looks like Apple has said that error is benign and can be ignored in 2010.
http://support.apple.com/kb/TS2028?viewlocale=en_US&locale=en_U
I do believe fsck will fix it though.
Some other results from the same search:
http://forums.macrumors.com/showthread.php?t=1071850
https://discussions.apple.com/thread/3635034?start=0&tstart=0

External hard drive won't mount, even after disk repair.

My Toshiba external hard drive won't mount on my MacBook Pro 10.8.5. I can see it in my disk repair, and when I repair, "the partition map appears to be ok." But I can't access the icon to be able to open the hard drive contents on my desktop. Help!

Hello maccynicwhoalwayshasmacs,
Thanks for the question. After reviewing your post, it sounds like trouble with an external HD mounting. I would recommend that you read this article, it may be able to help you resolve or isolate the issue.
USB and FireWire Quick Assist
Thanks for using Apple Support Communities.
Have a nice day,
Mario

Gray screen on start up and not able to repair hard disk and not able to take back up.

My macbook pro bought in early 2011 with snowleopard software and than upgraded to lion is now running on system 10.7.5 .
My problem is i get a gray screen on startup with apple logo and spinning ball.
I tried all the solutions mentioned in the apple support for "gray screen appears during start up". This Disk utility says that the Hard disk cant be repaired.
Before i format my disk and erase all data and install Mac os x again, i want to take back up on a external hard disk. I bought a new 2tb external hard disk so that i can take a back up.
As i try to take the backup of the image, it gives me an error "cannot allocate memory"
i tried to change the configuration from compressed to read/write and tried different encrption methods but unable to take backup.
i sometimes get error "input/output".
how do i take a backup. somebody please help

See OS X- Gray progress bar appears under Apple logo during startup. If you need to reinstall OS X, then do this:
Reinstall Lion, Mountain Lion, or Mavericks without erasing drive
Boot to the Recovery HD:
Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
Repair
When the recovery menu appears select Disk Utility. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported then click on the Repair Permissions button. When the process is completed, then quit DU and return to the main menu.
Reinstall Lion, Mountain Lion, or Mavericks
OS X Mavericks- Reinstall OS X
OS X Mountain Lion- Reinstall OS X
OS X Lion- Reinstall Mac OS X
Note: You will need an active Internet connection. I suggest using Ethernet
if possible because it is three times faster than wireless.

Disk Utility Hard Drive Repair Shows Following Message

Hi all
I have a Lacie FW800 External HD that was mounting on my desktop though slow to access earlier this morning.
I shut down and checked all FW 800 connections [some of the five connected drives have been daisy chained - 3 from the rear port and 2 from the front port]. I checked all power supplys also.
I then turned my machine back on and the slow hard drive would not mount and continues to fail to mount. I then opened Disk Utility from the Applications>Utilities folder/s and tried the Verify Disk option which then suggested to Repair the Disk. Unfortunately I received the following message as opposed to a "disk repaired" message.
\BEGIN TRANSCRIPT/
Verify and Repair disk “disk3s1”
Checking HFS Plus volume.
Invalid node structure
Invalid B-tree node size
Invalid node structure
Invalid B-tree node size
Volume check failed.
Error: The underlying task reported failure on exit
1 HFS volume checked
1 volume could not be repaired because of an error
\END TRANSCRIPT/
Does anyone have any ideas on what I can do to repair / reaccesss this HD. It is important that it continues to mount as it has current projects and important assets on board.
Please help asapc.
Thanks in advance.

Also, here is some information on data recovery if you think it would be worthwhile for you.
http://www.thexlab.com/faqs/datarecovery.html
Good luck,
Steve M.

Problems with hard disk, but it won't repair

Hi,
My MacBook Pro has gradually become slow, and it crashes occasionally, especially when multitasking. I verified my hard disk with the Disk Utility, and it told me the following:
Verifying volume “Macintosh HD”
Checking HFS Plus volume.
Checking Extents Overflow file.
Checking Catalog file.
Incorrect block count for file Temp File
(It should be 917 instead of 0)
Incorrect number of thread records
Checking multi-linked files.
Checking Catalog hierarchy.
Checking Extended Attributes file.
Checking volume bitmap.
Volume Bit Map needs minor repair
Checking volume information.
The volume Macintosh HD needs to be repaired.
Error: The underlying task reported failure on exit
1 HFS volume checked
Volume needs repair
However, in a pop-up it then says the following:
First Aid failed
Disk Utility stopped verifying "Macintosh HD" because the following error was encountered:
The underlying task reported failure on exit.
Any idea what could be wrong and how I could fix it? I find it a bit disconcerting that my Mac crashes. It's not supposed to do that!

In order to repair a startup volume you must boot from another disk. Try this:
Repairing the Hard Drive and Permissions
Boot from your OS X Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Installer menu (Utilities menu for Tiger and Leopard.) After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the installer. Now shutdown the computer for a couple of minutes and then restart normally.
If DU reports errors it cannot fix, then you will need Disk Warrior (4.1 for Leopard) and/or TechTool Pro (4.6.1 for Leopard) to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.

Disk Utility Unable to Repair External FireWire Hard Disk

Hello all.
This is the External FireWire Hard Disk that has been giving me problems for days, it is a Backup/Clone Disk of my sis's Mac mini Core Duo, and may explain why it was so hard and took so much pain to copy some of the data out, at times it failed to mount, and I manage to rescue some data after using Disk Warrior, but Disk Warrior was also unable to replace it with a new directory.
Anyway, so I (was able to) mount the hard disk, and I was successful in erase and reformating it.
But when I (try to) repair it with Disk Utility's First Aid, this report is what I get:
(The usual 'Checking...' text lines, text in BOLD indicates RED colour text)
Checking HFS Plus volume
Checking Extents Overflow file
Checking Catalog file
Checking Catalog hierarchy
Checking volume bitmap
Volume Bit Map needs minor repair
Checking volume information
The volume Untitled could not be repaired after 3 attempts
Error: The underlying task reported failure on exit
1 HFS volume checked
1 volume could not be repaired because of an error
Repair attempted on 1 volume
1 volume could not be repaired
Then a window dropped down from the top says:
First Aid failed
Disk Utility stopped repairing "Untitled" because the following error was encountered:
The underlying task reported failure on exit
(OK Button)
I guess this hard disk is really a gone case?? I am quite OK just to replace it with a brand new one... maybe all the trouble I had in the beginning is because I may already have a faulty backup drive to begin with???
Thanks and cheers

Hi Kappy,
I knew there was something about "not mixing" PPC and Intel versions of dealing with the external drive.
The drive was originally prepared on an Intel Mac mini Core Duo. But it should also mount normally on a PPC mac as an external hard drive right?
Here's the sequence of events:
1. Tried to boot from the Back Up/Clone Drive of the Mac mini Core Duo, through my MacBook Core 2 Duo, but failed to boot up
I had to shut down the MacBook (prolonged Bluescreen)
2. When I reboot the MacBook, and tried to mount the ext drive as normal, nothing happens, I knew something was wrong
3. Able to reach the vendor, use the Mac mini again to erase and reformat the drive, then check with DU, everything is OK
Clone with SuperDuper
After that check again with DU, not everything is alright, there are errors.
4. Brought the drive home, try to mount on my iMac G5, nothing happens.
I did a check on this forum, and the reply was that I should be able to use Disk Warrior 4 (Universal) on a PPC to fix an Intel-based ext drive. I was very specific and detail in my post/question
5. So anyway, I have no other option, I ran Disk Warrior 4 from my PPC iMac G5 and scan the ext drive, trying to fix it.
It reported the drive is too damaged to be replace with a new Directory, but gave me a Preview Mode. I use this to copy some data out.
But not sure if the data is OK or not.
6. After that, I was able to mount the drive in my iMac G5, so I just use DU and erase and reformat the drive, with Zero Data
7. Ran DU again, and that's where I am now, at the very first post, getting error messages that I cannot fix the drive
Thanks and cheers

My hard disk is damaged and i have no external hard drive, and i was wondering, if i sent my computer to Apple, would they back up my files for me before repairing it?

My hard disk has been damaged for about 4 months now. When I ran the disk repair under disk utility, it told me to back my files and send it in for repairs. My problem is that I had a external hard drive, but I lost it, so I obviously can't back up my files. Also I tried using other external hard drives and that didn't work, pretty sure it was because they were not formatted for a mac. So my question is that if I send my computer to Apple, for repair, that would they back up my files there before repairing my computer. It could be a dumb question but at least I asked. Also my mouse pad no longer works. The "clickability" of it stopped about 3 months or so after getting the computer and just around last Christmas the mouse would not click anymore at all, it would move if one put there fingers on the mousepad but it would not "touch click" anymore. So yeah, help!
And the OS X was still a snow leopard, not sure the number of the OS.

Can't you just get another external drive, format it for Mac OS Extended (Journaled) and backup some if not all of your files? Apple's not in the data recovery business. You should have maintained a backup and now it might be too late. Your best bet would probably be just to call it a loss and buy both an internal, to put in your machine, and an external, for backup purposes. You can boot from your installer disc, format the 'new' internal and begin restoring your apps at least.
I'll never understand why some people don't have backups. Drives fail. It's best to have redundant backups so that all three or four drives don't all fail at once.
Sheesh - I know that I'm not helping your problem but maybe now you've learned your lesson and others will as well.
Clinton

Should I backup my hard drive before I do a disk repair in disk utility?

I want to do a disk repair but I don't have an external hard drive to backup information on, so I'm wondering if I can just not back it up and do the disk repair? Does it kill information? How does disk repair even work? Is it a defragger?

You should always have a reasonably current backup and especially before any major software change such as an OS upgrade and, in this case, a disk repair. Running without a backup is like walking a tightrope without a net. External disks are inexpensive. Your data is not. Choose an external USB 3.0 disk that is double or more the size of your system disk and dedicate it as your Time Machine backup.
Time Machine Basics: http://support.apple.com/kb/ht1427
Most commonly used backup methods:
https://discussions.apple.com/docs/DOC-3045
A disk repair is actually a filesystem repair. It updates links that are in the filesystem directory. Usually this runs quickly and repairs any faulty links with no issues. It is a fairly safe action. Sometimes the directory cannot be repaired and the cure is to erase the disk, reinstall the OS and reload the data from a backup. Of course one does not erase the disk until they have completed the backup.
When you are ready to repair the disk:
Disk Utility 12.x: Repair a disk
http://support.apple.com/kb/PH5836

Since hard drive restore, backup gives Disk Repair, Read-only errors

Hi all -
After a hard drive crash last week, I restored the new HD using my historically reliable wireless Time Capsule (TC) with Time Machine (TM). But ever since, backups have ceased to work. Now, TM spins for about an hour before returning the following errors in sequence:
(1) DISK REPAIR: "The disk 'Backup of [my name] Macbook' was not repairable by this computer. It is being made available to you with limited functionality. You must back up your data and reformat the disk as soon as possible."
(2) TIME MACHINE ERROR: The backup volume is read only. To select a different volume, open System Preferences and choose Time Machine."
I very much doubt there is an actual problem with the TC disk itself; my wife's iBook G4 continues to backup to it without any problem whatsoever. Related threads have suggested:
a) doing clever things with Preferences, such as deleting the com.apple.TimeMachine.plist file and re-booting. However, for some reason (perhaps related to the source of the problem?) I have no such file...
b) using Disk Utility to re-format and/or re-partition (these terms mean little to me) the TC disk. But my Disk Utility doesn't see the TC. (Perhaps related, I no longer actually see the little backup disk icon on the desktop.) And as I've said, I doubt very much it's the TC disk itself that it is the problem.
I have of course tried re-booting everything, as well as un-mounting and re-mounting the TC: Computer, heal thyself! No luck.
Any guidance is appreciated...
(PS If there's a log file I should post that might help with diagnostics, just let me know where to find it.)

I have suffered the same error messages, but without a hard disk crash before it.
I copied the backup-file from the TC to a separate drive, erased the TC, re-installed it, copied the backup-file to the TC en re-initiated TM only to be welcomed with the 'The backup volume is read only'-message again.
Beats me why this happened. Most frustrating part, however, is that I am not able to restore from the backup-file. Any suggestions are highly appreciated!

Issues with Hard Drive & Disk Repair

I keep getting the following when I try to verify my hard drive with the Disk Utility:
Volume Header needs minor repair
The volume Macintosh HD needs to be repaired.
Error: The underlying task reported failure on exit
1 HFS volume checked
Volume needs repair
It won't let me go on to repair the disk and I can't find my Install/Restore disc anywhere. Is there a simple step-by-step way of fixing this?
Many Thanks
BH

Ben
Something to try if you can't find your Install disc is a Safe Boot: see Mac OS X: Starting up in Safe Mode and Mac OS X: What is Safe Boot, Safe Mode?. You should be aware that because of the disk checking, Safe Boot Takes Longer Than Normal Startup.
Safe Boot will run a full disk check, and re-run if it finds anything to repair. If it completes the booting process, it will have repaired your disk.
If your machine halts during Safe Boot, you have something seriously wrong with your disk: Mac OS X 10.4: Computer shuts down during Safe Boot.
If the latter happens, remember this quote from the Disk Utility screen:
• If Disk Utility cannot make repairs, try other disk repair programs or back up your data and erase the volume.One popular Repair Program is DiskWarrior.

HELP!!! Constant freezing, Bugged updates, Repair failure, and No Hard disk

Hi, I have had my iMac for just about a year now. It has never had any major problems up until now. One day, when i was using a downloaded non-Mac application that I had had for a while, my iMac freezes. Only the curser can move now. I pushed the power button putting the computer to sleep, then, waking it up again. All back to normal and I didn't think anything about it.
A couple of days later, it starst happening again, but with Mac applications too. It to the point to where i had to restart my computer by holing down the power button (aka. "the last resort"). It gets so bad to the point that I cannot use my computer anymore. The only thing I can do when it's frozen is move the curser, nothing else. So I take it to my local Apple Store. Guess what, it works perfectly when I turn it on there! Ha Ha Ha No. But yes it does work which is bad because he cannot fix a working computer. He repairs the permissions on the computer anyway, just to make sure. When I get home I power up my computer and it works aweful. Oh, and I forgot to mention earlier that it takes about 10-25 minutes to get to the login screen! Every time. So now I wait, without a computer for about a month until Christmas. I get the Drive Genius software by Prosoft for Christmas. So I use it to try to fix my iMac. I repaired everything possible to repair. So now the computer is working a lot better, but there are still some things that freeze. Such as, closing a window, or quitting an application, checking my email, and emtying the trash. A few weeks later I was calling an Apple support agent about a different product whitch was accually my fault but he gave me some suggestions to fix my computer. So I did the hardware test like he told me to and it did nothing. I did and archive and install and it worked!. So when you do one, there are like 20 things to update. I updated OS X first, then some other needed updates, when those were done and restarted I had planned on doing all of the security updates. On my second wave, the one right before the security updates, I restared my computer when the finished and then when I came back into the room, the screen was blue and had that little swirly gray loading thing. I left it on that for 6 or 7 hours hoping it would finally go through, but it did not. Back to the archive and install. I performed it once again and decided to change the order of the updates to, OS X, then all of the security ones, then everything else. it worked all of it. But, it eventually started freezing again. This time it was real freezing, the kind where your curser becomes a little "wheel of fortune" thing. BANKRUPT! I figured it was a bugged update because both failures happened close after the updates. It is archive and install time again. So I shut down my computer using "the last resort" while I am busy buying vowels and solving the puzzle. So I put the CD in and start. It took a little too long for the CD to find my hard disc. It made me nervous. I start the install but have to go. When I come bock to my house, the thing says "install failed please restart and try again". So I tried. but it never finds my hard disk. Its gone. Poof! I get the "no startup disk" floder sign on starup. One thing is that my Drive Genius software detects my disk easily. And that concludes my fairytale adventure.
Thanks and I hope somebody can help,
Jamey

Hey, thanks for responding. Well, first of all how do i a PMU? I have connected a logitech L/R click mouse with a scroll wheel, an Apple keyboard with an Apple brand keyboard USB extention cord, an iPod connector cord (no iPod connected), an HP PSC 1200 series all-in-one printer, and some non-Apple speakers. All of the computers in my house are on a airport express wireless internet system. At the Apple store all I had was an Apple mouse, Apple keyboard. Would it make any difference how I plugged these in? I have a battery backup system. Plugged into that are the following: (under battery backup and surge protector) my computer and my printer. (Under just surge protector) another power strip with surge protecctor and isolated outlets. On that are my speakers, my cell phone charger, my neon clock, and my desk light.
Thanks, I hope this information helps you help me resolve my problem,
Jamey

Can't repair or partition internal hard disk with disk utility

Hi,
For the past couple months I've been trying to repair and (re)format my second internal hard disk. It stopped showing up on the desktop after I attempted to install leopard on it. Until then I'd had no problems with the disk for the two years I've had it Leopard installed fine on the other smaller internal disk. But the second disk only shows up in disk utilities - it doesn't have any volumes. I can't verity the disk because the button is greyed out as is the repair disk button.
S.M.A.R.T. Status shows "not supported".
Partition Map Scheme shows "unformatted".
Whenever I startup my computer I get a dialog box stating "The disk I have inserted is unreadable by this computer". I't referring to my 250gig internal disk. I read some posts here that suggested using OS 10.4 disk utility to format but that doesn't work either.
At this point I'm totally lost as are all the files I had on that disk - I initially erased it back when I attempted to install leopard on it. Does anybody have any ideas how to fix this?
Thanks for any and all help

Hi V.K.
Thanks for the advice. Luckily I don't have any data on it since I wiped it clean back when I attempted to install leopard on it a couple months ago. I'm really amazed that it only lasted two years compared to my 80gig which has been in use [daily] for at least five years. I hardly ever used the 250gig drive. I ordered another (500gig) drive from Western Digital which I expect to be here in a couple days. In the mean time I guess I'll get out my hammer.
Thanks for your help.

Hard Disk Repairing

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