External drive is suddenly read-only, yet is formatted for Mac

I've had a 1TB external hard drive for the last year and never had a problem with it until now. Suddenly, it is showing as read-only, however, it's formatted for Mac. How am I able to fix this? Do I have to re-format it?

Usually that means the drive is malfunctioning. Back up all data on it, if you haven't already done so, then erase and restore. If you ever have another problem with the drive, replace it.

Similar Messages

  • External drives mount as read only

    I am running OS X 10.6, on a MacPro. Something happened recently to make my external hard drives mount as read only. The only way I've found to be able to fix them is to run Disk Utility every time I start up my computer. Does anyone have an solution to this?
    Also every time I run the Disk Utility, at the end of the repairs it says "Updating boot support partitions for the volume as required." I do not know if this is related, but I haven't been able to find anything relevant in relation to my problem with the drives mounting as read only.
    Message was edited by: HeatherK

    You might give this a try:
    Select the drive and Press COMMAND-I to open the Get Info window. At the bottom open the Ownership and Sharing section. Be sure the box labeled "Ignore permissions on this volume" is unchecked. If it is checked then click on the lock icon, authenticate, then uncheck that box. Close the window.
    Open the Terminal application in your Utilities folder and at the prompt enter or paste the following:
    sudo chown root:admin
    Put a space after "admin" then drag the drive's icon into the Terminal window. Press RETURN. You will be prompted to enter your admin password which will not be echoed.
    See if this fixes the problem.

  • External drive reverts to read-only on reboot

    My 2TB firewire drive becomes a read-only drive after a computer reboot.  From a cold start, drives boots to read-write.  How do I fix this?

    Nicky McCatty wrote:
    Earlier this morning my external drive, a Western Digital Firewire 800 1TB, was behaving normally. I shut my MacBook Pro down, and took it out for two hours. When I returned, Time Machine reported that my drive appeared to be read-only. I see that BOTH of my external Firewires now show up as read-only.
    What causes this to happen, and what can I do about this problem?
    A number of things. Most common is probably a power loss; second is probably disconnecting without first ejecting.
    It's not permissions; try running +*Repair Disk+* on them, per #A5 in Time Machine - Troubleshooting (or use the link in *User Tips* at the top of this forum).

  • External Hard drive is suddenly Read only.  Help!

    I reformatted my I mac due to it being extremely slow. After reformat, the toshiba external hard drive that I have been using for months before with no problem, is now a read only. I have over 1TB of space available and I need to use it. Does anyone know what happened and how to fix it. I cant lose my information.

    In the Finder, press the key combination shift-command-C, or select
    Go ▹ Computer
    from the menu bar. A window will open showing all mounted volumes. Select the one in question and open the Info window. What is shown as the Format in the General section?

  • External drive changed to read-only

    I have a Western Digital external drive that I use for Time Capsule and Super Duper! This morning, when I wanted to start work, Time Capsule said that my drive "appears to be a read-only drive," and Super Duper had failed its overnight backup.
    I used BatChMod, and changed the permissions.
    When I opened a finder window for the external, it still showed the read-only icon in the lower left hand corner of the window.
    The Get Info window shows System as the owner, Admin as the group, with all permissions. EVERYONE has read-only permission.
    When I look at the disk in Disk Utility, Repair Disk Permissions is greyed out.
    What would change the disk's status, and how can I fix this?
    Thanks,
    Nicky

    Most likely, your backups were corrupted, beyond Disk Utility's ability to repair them. It's possible a 3rd party disk repair app, such as +Disk Warrior,+ could have fixed them, but it's too late now.
    Does the drive have two partitions, one for Time Machine backups, and a second for SuperDuper? If so, erase the Time Machine partition and let TM start over.
    If not, that's a problem (see #3 in the Frequently Asked Questions *User Tip,* also at the top of this forum). Your best bet is to reformat the disk with two partitions. See #5 in the FAQ for detailed instructions. Then start both Time Machine and SuperDuper over fresh.
    Longer-term, having both backups on the same physical drive is not good; if the drive fails, you risk losing both of them.

  • After moving iTunes, external drive sometimes becomes read-only after reboot

    I had some system corruption a few weeks ago, and had to restore my system.  As part of that prolonged effort, I decided to move my iPhoto Library and iTunes Library to external FW800 drives.
    I had terrible problems initially with these drives mounting read-only.  I found a relatively quick work-around, and that seemed to fix the problem.  But I still have them periodically mount read-only, and I can't D/L iTunes updates, etc.
    Why do they keep doing this on a reboot?  Very frustrating, as I need to reboot as part of the fix, and I'm always in the middle of something else, and can't reboot at that time.

    Oh, as part of this, not sure when the change was made, OSX used to keep the mounted volume name in /Volumes, even if the volume was ejected.  Would cause an occasional problem - but very rare.  I notice now that ML seems to create/delete these mountpoints automagically - and that's part of the problem.  They get incorrect permissions when the volume mounts, and I (user I'm logged in as), can't write to the volume without some background shenanigans.
    My process is this:
    Unmount problem volume
    Drop to terminal, and "sudo mkdir /Volumes/<mounted_volume_name>"
    Remount volume via Disk Utility (you now get a "<mounted_volume_name> 1" - with CORRECT permissions)
    Unmount the volume again
    Remove the created directory (i.e. undo step 2)
    Remount the volume - 99.9% of the time that seems to fix it.
    Reboot to be sure - and it stays for a while - then at some point becomes a problem again.
    Not sure if it's something in ML that's an issue - or something in iTunes or iPhoto (but can't see how they would affect the permissions when the system reboots and you login)

  • External drive reverts to read-only on airport extreme

    I have an external drive that works fine (full access read/write) when connected directly to my Macbook but reverts to read-only when I connect to it through my airport extreme.  It also won't let me change the permisssions over the network.  I have another drive used for Time Capsule connected to the Airport Extreme and it works fine, as well as the printer.  The problem drive is formatted OS X extended (journaled).

    Nicky McCatty wrote:
    Earlier this morning my external drive, a Western Digital Firewire 800 1TB, was behaving normally. I shut my MacBook Pro down, and took it out for two hours. When I returned, Time Machine reported that my drive appeared to be read-only. I see that BOTH of my external Firewires now show up as read-only.
    What causes this to happen, and what can I do about this problem?
    A number of things. Most common is probably a power loss; second is probably disconnecting without first ejecting.
    It's not permissions; try running +*Repair Disk+* on them, per #A5 in Time Machine - Troubleshooting (or use the link in *User Tips* at the top of this forum).

  • External volume is suddenly read only

    Mountain Lion on 2009 Macbook Pro. I have a Drobo S with three volumes. One of the volumes has become read-only. I cannot change this in the Finder. This happened with a different volume a couple of days ago. This never happened before I upgraded to Mountain Lion three days ago. Restarting has fixed the problem both times. but it is a pain and can be a big problem if it returns in the middle of a write or large backup.
    Here is a screen grab of the volume info in the Finder.
    What is happening and how do I prevent this?

    Usually that means the drive is malfunctioning. Back up all data on it, if you haven't already done so, then erase and restore. If you ever have another problem with the drive, replace it.

  • I have a FAT 32 External Hard Drive marked as Read Only that is unchangeable by an administrator or root user, how can I make it read/Write

    Hello, All,
    I have a FAT 32 External Hard Drive marked as Read Only that is unchangeable by an administrator or root user, how can I make it read/Write without reformatting it ? 

    Hi Kappy,
    Just wondering if you had any advice for my situation . . .
    My time machine backup was backing up to a drive that was "Mac OS X Enteded Journaled, Case Sensitive."  I had no idea what this meant, or that it would even cause issues.
    I took my computer to the Apple store yesterday, and they wiped it clean.  When they tried to restore it from the Time Machine backup drive, it would not work.  Their guess is that Time Machine cannot restore from a drive that is "case sensitive."
    Any thoughts on how I can convert my time machine backup data from a "case sensitive" state, to a "non-case sensitive" state?  I've tried to just drag and drop the files from the case sensitive formatted drive to a new drive that I have that is formatted non case sensitive, but I get the following error message:
    "The volume has the wrong case sensitivity for a backup"
    I just really want my data back - I thought TimeMachine was the way to go (and was supposed to work) but unfortunately it is not.
    Any help you can provide would be greatly appreciated.
    Thanks,

  • My mac mini won't back up to my Seagate external drive but can read the information on it. Can i back up to it at all?

    My mac mini won't back up to my Seagate external drive but can read the information on it.
    Can i back up to it at all? and how do i do it?
    Simon

    I suspect the Seagate is not formatted to be used with the Mac. The correct format would be Mac OS Extended (Journaled), if you just bought the EHD then almost certainly it's formatted to be used with MS Windows machines. This is easy to fix, here are instructions on how to format it:
    http://pondini.org/OSX/DU1.html
    After formatting Time Machine http://support.apple.com/kb/ht1427 will launch and will begin backing up. The first backup will take some time however after the first backup it will go pretty quickly.
    NOTE!!!!!!!!!!!!!!! After formatting all data will be erased, so please if you have data on that move it to the internal HD first and then format. Then once you have backed up you will have a backup copy of the data. Also NEVER EVER use a backup disk to be used to store data. The reason being is if that drive crashes you have not only lost the data you have lost it's backup!!!!!!!!!!!!!!!

  • Drive changes to read only

    I am new to mac. I have a new 27" IMac. I purchased this computer strictly for photo processing
    I have 3 external drives
    1. Time Machine backup - Seagate 3TB  - No problemn with this drive right out of the box
    2. Photo Drive - Seagate 2TB Firewire drive- Photo library is 1.4TB
    3. Original Photos -Seagate 2 TB USB drive Small amout of data but have used this for backup while reformating the photo drive
    1TB Internal drive that only contains the OS and Programs. Mainly Adobe Lightroom and Photoshop
    The Photo Drive was purchased as ready for PC or Mac
    I pluged it in and it worked just long enough to load all my photos and get things organized.
    The 2TB Original Photo drive was originall used for PC and I discovered I could not write to this drive so I reformatted to OS Journaled.
    Next, My main Photo drive became read only - Error message stated I need to refornat the drive - Error 36
    I transfered all Photos to Original, Reformated Photos as OS Journaled and then transfered files from Origianl back to Photo
    All sorded for a a couple of weeks then the Origial drive became read only and I have to format it again.
    Since then, the photo drive has become read only two more times.
    I just finished reloading the photo drive for the third time on Thursday. For the last 3 days I have been Importing new photos from several weeks of shooting.
    All seemd fine untill today. I tried to create a folder and discovered the photo drive is once again read only. The Original photos drive is still read / write.
    I have read everything I can online. It seems other people have had similar problems but I found no solutions.
    Currently the photo drive info is as follows
    Flormat Mac OS Extended - I'm sure I selected Journaled on the last format
    Sharing and permissions
    "You can only read" is at the top
    followed in black text
         Paul (Me) Read & Write
         Staff Read & Write
         Everyone Read & Write - (I changed this after formatting and before reloading the drive thinking it might help)
         Ignore ownership is checked
    I can unlock the pad lock Icon but I cannot change anything except I can uncheck and recheck Ignor ownership. However this still does not allow me to make any changes.
    One clue I may have to offer
    I use a small Seagate drive named Transfer Drive which I use in the field.
    It is formated NTFS
    I download photos from my photo cards to my PC notebook and back them up to the Transfer drive
    When I get home I import photos from the Transfer drive to my iMac using Lightroom
    This was the last action I performed yesterday. I performed 8 imports from the Transfer drive to My imac with Lightroom
    Is it possible that importing from a NTFS drive to the external Photo drive is causing this problem?
    I really need to solve this. It takes about 3 days for me to move my photo library and reformat the drive
    Not to mention the fact that I am very worried about my photo files.
    Thank you in advance
    Paul McCroskey

    There may be a solution here, but I would modify the instructions to say that if Verify disk shows OK, you don't need to go on to Repair.
    https://discussions.apple.com/message/18266486#18266486
    First, copy/paste, leave a space after -alO and drag Photos into the Terminal window and hit return.
    ls -alO
    If the output shows the uchg flag, the immutable (locked) flag, then run the following to remove it.
    sudo chflags nouchg /Volumes/Photos
    If that doesn't fix it, then Verify Disk. If that shows an error, then follow the instructions to copy the data elsewhere first, then run Disk repair. Sometimes, though this is rare, disk repair can make things worse.
    (After removing the immutable flag -- if it proves necessary -- you may still have to go on and run the commands you tried earlier.)

  • External harddrive limited to 'read only'

    I have a hard drive that is set to 'read only' and is formatted as NTFS.  How can I change this so that I can save files to the disk, without reformattin and losing everything on the drive?

    Best is to connect that external to a Windows PC, Copy all the files off it then format it either FAT32 or exFAT on the Windows PC. That way both Windows and OS X can write and read from it.
    3rd party software will work but can be problematic.

  • TS1550 Back up to time machine failed.  Error, "Files can't be copied onto the backup disk because it appears to be read-only". Back up has been working.  drive is not read only.  How do I fix this?

    Back up to time machine failed.  Error, "Files can’t be copied onto the backup disk because it appears to be read-only". Back up has been working.  drive is not read only.  How do I fix this?

    Hello,
    http://pondini.org/TM/C6.html

  • Since I upgraded to 10.9.5, my macbook no longer recognizes my external  hard drive. How do I fix this?  External hard drive is a 1TB Toshiba formatted for mac.  Worked fine until latest upgrade.

    Since I upgraded to 10.9.5, my macbook no longer recognizes my external  hard drive. How do I fix this?  External hard drive is a 1TB Toshiba formatted for mac.  Worked fine until latest upgrade.

    Solved the problem by dumping my external HD onto another computer. Re-formatting and re-installing the data.  Not what I wanted to do but it solved the problem.

  • I want to copy my iPhoto library to an external drive but I cannot find the folder on my Mac Air. When I open Finder there is no Picture folder showing so I cannot find the iPhoto library.

    I want to copy my iPhoto library to an external drive but I cannot find the folder on my Mac Air. When I open Finder there is no Picture folder showing so I cannot find the iPhoto library.

    Choose Go to Folder from the Finder's Go menu and provide ~/Pictures/ as the path. If that doesn't work, control-click a photo in iPhoto, show it in the Finder, and Command-click the folder's name in the window's title bar to find the path.
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