External Drive Unmounting?

I have 2 G-Drives daisy chained via fire wire 800 to my iMac. I mac set set to never sleep.
My external drive is set to wake for access. The problem is over night my iMac losses the
external g-drive. Sometimes it looses both other times it drops the second one in the chain.
Now I can leave the drives to never sleep but rather not. Any suggestions as what is causing this problem?

I have this exact same problem. But with respect to the helpful advice above, I don't think this is related to a bad SATA bridge. (At least, in my case). The reason I think this is because:
This problem only occurs when I connect the external drive to my iMac (late 2103, 3.4 Ghz CPU, Fusion drive, etc)
Everything works perfectly fine if I connect to a USB 2.0 port on my older Macbook pro.
Everything works perfectly fine if I connect to my Windows 7 laptop using USB-3.
I am pretty sure this is related to the iMac hardware. Some things I read suggested the iMac might not have enough power being supplied to the external drive. (Even though the drive enclosure has its own power supply)
The drive manufacturer suggesed I connect the device using a powered USB hub. That would make sense in a way, although I don't want to have to buy a powered USB-3 hub just to connect a single external hard drive!
The only other devices I have connected via USB are my apple keyboard.
Does anybody else have any other thoughts?
I am using OS 10.9.0 (Mavericks), which is currently the most recent version of OS X.

Similar Messages

External Drive UNMOUNTING On Its Own...

Hello.
I have a quite-brand new Iomega External Drive FireWire 800 2TB, bought recently to replace my old failed drive, to be a Time Machine Drive for my iMac.
For the past few days I have observed something very very strange: This TM Drive will for no reason, unmount itself from the Desktop; Sometimes I will be at the computer and that usual warning window message about not unmounting your external drive properly will appear. But sometimes when I get back to my iMac, the ext drive has already unmounted, not sure for how long since the icon is not there anymore.
I just have to turn off and on the drive again to get it mounted.
Before this strange thing, there was a couple of times when TM failed to back up, but it was nothing serious, I just back up again and it is fine. There was once prior to this, that I re-format the drive again (GUID partition) and TM all over again.
I ran Disk Utilities and it says the drive is OK and need no repairs.
So what went wrong here? I have doubts that the drive is faulty because I just got it recently as a new replacement to a previous dead drive. Could it be the iMac itself? The OS? Or the physical FW800 port itself?
Need some advice and help, thanks and cheers

Over the last few days, I have noticed this behaviour (external drive unmounting itself), but I have a 2TB Western Digital USB2 My Book Mac Edition drive that has been working fine with Apple's Backup program since I bought the drive exactly one month ago. The Backup files have now half-filled the drive, and when Backup is attempting to save a new file the drive unmounts and the backup fails. Hers is the backup log from Console for the last couple of days (Cassini is the name of the WD external drive):
2010-11-18 11:54:05.080 Backup[22672:8537] debug: unable to test mount disk image {
"image-components" = (
"/Volumes/Cassini/Backups/Phobos - 2010.11.18-00.30.22.847.backXX/Contents/Contents/Backup.sparseimage"
"shadow-file" = "(null)";
"system-entities" = "(null)";
2010-11-18 11:54:05.107 Backup[22672:8b03] unable to gzip /Volumes/Cassini/Backups/Phobos - 2010.11.18-00.30.22.847.backXX/Contents/backup.log: file does not exist
2010-11-19 08:42:53.803 Backup[22672:bb9f] debug: unable to rename disk image {
"image-components" = (
"/Volumes/Cassini/Backups/Phobos - 2010.11.19-07.36.08.399.backXX/Contents/Contents/311805478.972355.sparseimage"
"shadow-file" = "(null)";
"system-entities" = "(null)";
2010-11-19 08:42:53.848 Backup[22672:9e3f] unable to gzip /Volumes/Cassini/Backups/Phobos - 2010.11.19-07.36.08.399.backXX/Contents/backup.log: file does not exist

External drive unmounting periodically

Hi all,
I've been using an external drive for time machine and cloning of my imac hard drive (each on their own partition). This setup has been working flawlessly for the past 6-7 months.
Just recently TM backups have failed to run and it appears that the external disk is shutting down or unmounted or something (the drive icons on the desktop disappear anyway).
So far if I unplug the power cord or the FW800 cord to the drive and re-insert the imac promptly sees the drive again and all is well.
The first time this happened I just put it down to bad luck or power spike or something, but for the last week or two the drive is disappearing in a day or two. I leave my mac on pretty much 24/7.
Any ideas ? I've also pinged the drive manufacturer WD too.
Not sure if its significant but I have an apogee duet daisy chained off the FW800 system as well, but thats also been there for a few months.
Thanks

Related to the other reply, I had a somewhat similar issue with two Firewire drives daisy-chained together to my iMac. It turned out to be because the first drive in the chain does not pass Firewire signals between its ports when it is powered down. (Some do, some don't.) As long as the first drive was powered up, the second drive was fine, but if the first powered down, I got a warning saying the second was unmounted incorrectly.
Because the first drive has an automatic power down on computer sleep feature, & it takes about 10 seconds after the Mac wakes for it to decide to power back up, I would sometimes see this happen just by sleeping & waking the Mac, depending on how quickly the OS tried to access the second drive.
I don't know if this applies to the devices on your Firewire chain but it is something to check.

External drive unmounted improperly

AS part of the Hard Drive Replacement Program for my iMac, I was restoring iMovie events from external disk (iomega usb 1 TB drive), the application froze and the external drive was unmounted improperly and now I cannot remount. In the past, I had a unix guru perfrom a command to unmount and then remount and it worked. I have tried unsuccessfully to recreate. Can you help?
iMac 27" Intel, OSX 10.6.8

for log file
07:03:56 filesystems have been refreshed.
07:03:56   created filesystem, id = /System/Library/Filesystems/afpfs.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/cd9660.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/cddafs.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/exfat.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/ftp.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/hfs.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/msdos.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/nfs.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/nofs.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/ntfs.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/smbfs.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/udf.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/ufs.fs/.
07:03:56   created filesystem, id = /System/Library/Filesystems/webdav.fs/.
07:03:56
07:03:56 iokit [0] -> diskarbitrationd [220]
07:03:56   created disk, id = /dev/disk0s2.
07:03:56   created disk, id = /dev/disk0s1.
07:03:56   created disk, id = /dev/disk0.
07:03:56   created disk, id = /dev/disk1s3.
07:03:56   created disk, id = /dev/disk1s2.
07:03:56   created disk, id = /dev/disk1s1.
07:03:56   created disk, id = /dev/disk1.
07:03:56
07:03:56 diskarbitrationd [220] -> diskarbitrationd [220]
07:03:56   probed disk, id = /dev/disk1s1, with hfs, ongoing.
07:03:56   probed disk, id = /dev/disk0s2, with hfs, ongoing.
07:03:56   probed disk, id = /dev/disk1s1, with hfs, success.
07:03:56   probed disk, id = /dev/disk1s2, with hfs, ongoing.
07:03:56   probed disk, id = /dev/disk1s2, with hfs, success.
07:03:56   probed disk, id = /dev/disk1s3, with msdos, ongoing.
07:03:56   probed disk, id = /dev/disk0s2, with hfs, success.
07:03:56   probed disk, id = /dev/disk1s3, with msdos, failure.
07:03:56 unable to probe /dev/disk1s3 (status code 0xFFFFFFFC).
07:03:56   probed disk, id = /dev/disk1s3, no match.

External drive unmountable & invisible after sleep (osx 10.8.1)

Hello,
yesterday evening, the lid of my mbp (retina, medio 2012) was closed while it was displaying the screensaver, with an external USB disk plugged in.
After I opened the lid and logged back in, I saw a dialog mentioning that the disk was removed without being properly unmounted.
Since then. I have not only been able to mount it; but it doesn't show up at all.
Not in the finder, not in Disk Utility, not in the Terminal under /Volumes or under /dev/...
I tried the following, so far without any result:
restarting the Finder
rebooting the machine
resetting the pram & nvram
trying the disk on another mac
using either one of the MBP's two USB slots
I have used this disk in this enclosure to store my photo's and music on, until yesterday without any problems. The only thing that I wondered about was that it did not seem a lot faster than I was used to with USB 2 - but that wasn't really an issue.
Further details:
The disk is a 2.5 inch 700 GB disk in a USB 3.0 enclosure. It's formatted as Mac OS Extended (Journaled).
The disk has been used only a few months without any prior problems.
The enclosure is a König CMP-MOBSTOR96, it's about a month old.
The disk has run fine until now without using an additional power supply. There is, however, a 5 volt input on the enclosure.
The enclosure is connected to the MBP via the USB 3.0 cable that came with the enclosure.
I looked in the Console messages, and found that there were a couple of messages apparently related to this issue:
04-09-12 13:42:55,000 kernel[0]: USBF:
2540.458
[0xffffff802ed5ce00] The IOUSBFamily is having trouble enumerating a USB device that has been plugged in. It will keep retrying. (Port 2 of Hub at 0x14000000)
04-09-12 13:42:59,000 kernel[0]: USBF:
2544.946
[0xffffff802ed5ce00] The IOUSBFamily was not able to enumerate a device.
04-09-12 13:43:01,000 kernel[0]: USBF:
2546.268
[0xffffff802ed5ce00] The IOUSBFamily is having trouble enumerating a USB device that has been plugged in. It will keep retrying. (Port 2 of Hub at 0x14000000)
04-09-12 13:43:05,000 kernel[0]: USBF:
2551.148
[0xffffff802ed5ce00] The IOUSBFamily was not able to enumerate a device.
04-09-12 13:43:07,000 kernel[0]: USBF:
2552.470
[0xffffff802ed5ce00] The IOUSBFamily is having trouble enumerating a USB device that has been plugged in. It will keep retrying. (Port 2 of Hub at 0x14000000)
04-09-12 13:43:08,000 kernel[0]: USBF:
2553.790
[0xffffff802ed5ce00] The IOUSBFamily gave up enumerating a USB device after 10 retries. (Port 2 of Hub at 0x14000000)
04-09-12 13:43:08,000 kernel[0]: USBF:
2553.790
[0xffffff802ed5ce00] The IOUSBFamily was not able to enumerate a device.
I found some discussions googling for these messages that seemed to suggest that the cause of the problem is either the cable, insufficient power available to the drive, or failure of the enclosure.
But because this issue happened directly after the "disk not unmounted properly" warning message that followed the closing and opening of the MBP lid, it would be very unlikely that the enclosure or cable would have failed at exactly the same time.
I can (and will) get another enclosure and try it with that, but I was wondering if anyone had any other suggestions that I could look into? It is in any case a bit awkward that problems if this caliber arise after someone merely shuts the lid of the computer causing it to sleep. Also. it was in all likelyhood not writing to the disk at that time.
Thanks in advance!

update
I had kept the electronics part (with the SATA and USB connectors) of a damaged USB 2.0 enclosure. Using that on the above drive DOES work. Also reversely, putting another (known working) drive in the enclosure also fails to show up on the MBP.
Apparently, either the enclosure or the USB cable is broken. That's not strange in itself. But what puzzles me a lot is that it broke at the exact time that the lid of the MBP was closed (for a few minutes) and opened again, causing the "disk not unmounted properly" warning.
I'd really like to know if there is any imaginable way in which the one can have caused the other.
Of course, it is also possible that it is not truly broken but that it somehow, suddenly found the power supply through the USB cable insufficient. Which would be even weirder.
The good thing is that my data and disk are fine. Replacing the enclosure isn't a big deal. But I am hugely confused.

Western Digital External Drive unmounts when USB used

I have a Western Digital 1TB My Book Studio edition external HDD. Its been unmounting recently without warning. I fianlly narrowed it down to when I plug or unplug a USB device such as a headset.
The drive is running in FW as I dont have any spare USB ports. WD are now blaming the computer. After reading other issues people have had with WD I dont believe them. I'm about to install 10.5.8 but I doubt this will fix it, also the HDD has the latest firmware.
Has anyone else had this sort of problem or have any suggestions?

I have a Western Digital 500 GB My Book that mysteriously mounts or doesn't mount about 50% of the time. Am using it in FW, though I've also tried USB with no change in behavior.
The drive gets fiercely hot - I suspect this might be contributing to the bad behavior of the drive. If I check the System Profiler when the drive doesn't mount, it is showing in the System Profiler - but doesn't appear on my desktop.
Out-of-warrantee support is $50 - or I can throw it out and buy a different brand for about $100! Guess which one I will choose!

How to recover files off unmountable seagate external drive

I have been using a Seagate Backup Plus external drive for several months on my iMac destop. The external drive runs off of USB no other power source. I unmounted it the other day to use on my mac power pc and transferred mp4 files onto drive without problems. Unmounted drive and plugged it back to iMac and I am getting prompt The disk you inserted was not readable by this computer choices of initialize, ignore, eject buttons. I have shut down and plugged it back in and reset the PRAM. I can see the unmounted device in disk utility and also I can see that it's plugged into the USB port. I have tried plugging the device into the mac power pc, macbook and pc all but pc give me the same response. On the PC I can't see the drive at all, though it has power and can be ejected. I would like to find out how to mount this drive to retrieve the files off of it. I am also wondering what to do with this drive, ie.e reformat it (if and when I retrieve files) or try to return it (bought it in Sept. 2012). Any help on this subject is greatly appreciated!

I did try Disk Utility Repair disk command, but when I ran it this is the report I received:
2013-03-07 17:02:52 -0500: Verify and Repair volume “disk1s3”
2013-03-07 17:02:52 -0500: Starting repair tool:
2013-03-07 17:02:52 -0500: Checking file system2013-03-07 17:02:52 -0500: Checking Journaled HFS Plus volume.
2013-03-07 17:02:52 -0500: Invalid node structure
2013-03-07 17:02:52 -0500: Invalid B-tree node size
2013-03-07 17:02:52 -0500: Invalid node structure
2013-03-07 17:02:52 -0500: Invalid B-tree node size
2013-03-07 17:02:52 -0500: The volume could not be verified completely.
2013-03-07 17:02:52 -0500: Volume repair complete.
2013-03-07 17:02:52 -0500: Updating boot support partitions for the volume as required.2013-03-07 17:02:52 -0500: Error: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files.
Disk Utility stopped repairing “disk1s3”: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files.
I was trying to recover data without purchasing software if at all possible.

External drive no longer mounts or unmounts or formats. Help!

I have a 1TB external Seagate drive which is used to store my time machine backup for an iMac (2010). My time machine is failing as it says there is no backup disk. I ran disk utility. I see it on the external drive on the list below the line on the drive listings. I see the external drive and the time machine volume indented below it. I verified the external disk and it says it is fine. However it will not let me mount the external drive or the time machine partition. I cannot even re-format the disk because it says it cannot be unmounted (which is obvious it it does not let me mount it). It is connecting to the drive because it can see the verify results. I also tried every combination of unplugging power and cables to both the unit and the Mac itself.
Question(s):
1. Is there anyway to remount the external seagate drive?
2. Can I format it without mounting it. I don't care if I lose anything as it is all time machine backup files only
3. Do I need to format it on my windows PC and then reformat it again on a Mac!?
Help I am at my wit's end!!
Thanks
RZ

Disk Utility - Format, Erase, or Reformat a Drive

Mavericks and unmounting external drive issues upon sleep

Greetings fellow Mavericks users,
I'm hoping someone here can provide some insight as to how to correct the issue I'm experiencing.
Little background:
I was using 10.6.8 for years on a 2008 Mac Pro. I saw no reason to update the OS until I recently acquired a USB 3.0 PCI card and an external drive. In order to use my new hardware, I had no choice but to upgrade to a new version of OSX. Rather than spend money, I took advantage of the free 10.9.2 upgrade available for my machine. The upgrade went surprisingly well with no major hiccups or problems encountered. Yes, a few apps and programs I had running prior to the upgrade were no longer compatible but in the grand scheme of things, my Mac Pro was still alive and kicking along with my most important programs and data. In fact, the upgrade to 10.9.2 fixed a sleep issue I had with 10.6.8 which required the use of an app called PleaseSleep. I don't need that app anymore as the machine goes to sleep and wakes up fine.
Now, on to my dilemma. Prior to the upgrade, I was using an external USB 2.0 drive to house media that I'd share between multiple network devices around the house via SMB (AFP stinks in this regard, hence my refusal to use it); i.e. BoxeeBox. I had run out of space on the USB2 drive hence the need to move everything to my new external USB3 drive that's connected to an internal USB3 PCI controller. The first problem I ran into was that Mavericks now uses Apple's own iteration of Samba (SMB2). After a bit of head scratching and research, I used an application called SMBUp as a replacement to Apple's SMB implementation. That's one problem solved. The next thing that I kept running into was that whenever the machine would sleep then wake up again, I'd get an annoying "Disk was not properly ejected" error message. After more head scratching and research, I've discovered that this appears to be a bug in OSX and how the OS interfaces with 3rd party USB controllers. Fine. I purchased a small app called Jettison which for all intents and purposes unmounts any external drives automatically before allowing the system to sleep. This is where my long-winded (apologies) description above starts to come into play. Now that I have the SMB issue figured out and am using Jettison to eject this USB3 drive when the machine sleeps, I've discovered that I'll still get the "Disk did not properly eject" error message despite Jettison IF there are users connected to the USB3 media drive. Is there a work around this where I can either get Jettison or Mavericks to kill the network connection to the share drive before it's unmounted prior to the machine sleeping?
TL:DR?
Using Jettison with Mavericks, I'm still getting "Disk did not eject properly" when waking the machine from sleep mode. Any way to fix this?
Thanks in advance for any help/suggestions provided.

I had the same problem with Time Machine and solved it by enabling "Enable Power Nap" in Energy Saver:
System Preferences...
Energy Saver
Restore Defaults
Check "Enable Power Nap: While sleeping, your Mac can back up using Time Machine and periodically check for new email, calendar, and other iCloud updates."
2013 21.5 iMac
OSX Mavericks
Seagate 1 TB slim USB 3.0 (power is drawn from USB port), formatted to Mac Journaling File System

My external drive is always unmounted?

Hi. I have a 2TB external drive that I have been using for two years, without ever having any problems with it - until now.
Everytime I plug it in my Macbook Air, it doesn't show up my desktop, and when I go to Disk Utility it says that the disk is unmounted. Then I usually have to verify the disk once, and repair it twice to get it to show up on the desktop and to work properly, but if I eject it and plug it back in, the same thing happens again.
When I plug it in a Windows computer, it shows up immediately, without any problems - however, the last time I did this, a 1TB folder full of movies and tv shows was deleted from the drive. Also - the external drive is in an exfat format.
Does anyone know anything that I could do?

Finder -> Preferences -> General -> Show these items on desktop -> External disks

Format External Drive Error can't unmount disk LaCie 1TB External Drive

Need Help Can't Format This disk. I have tried Formating with Disk Utility and It says it can't be unmounted.
Help!!

Drive Partition and Format
1. 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 Utilities menu.
If you are preparing an external or a non-startup drive, then open Disk Utility in your Utilities folder.
2. After Disk Utility loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. SMART info will not be reported on external drives. Otherwise, click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Apply button and wait until the process has completed.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled.) Click on the Security button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.
Steps 4-6 are optional but should be used on a drive that has never been formatted before, if the format type is not Mac OS Extended, if the partition scheme has been changed, or if a different operating system (not OS X) has been installed on the drive.

Discussion regarding un-unmountable external drives and more..

I have a Mac OS Extended (Journaled) formatted LaCie 2TB external USB 2.0 hard drive which I use for backup and file storage with my MBP running snow leopard. Some times when working extremely large folders at work, I actually work right of the hard drive and it works very well. But I have observed an increasingly annoying problem.
If I keep the drive active and working with whatever for a while and then decide to eject the disk, this almost always causes headaches. Either I get these warnings that the disk cannot be ejected because; Mail is using the drive, Safari is using the drive, Itunes is using the drive...... or some other app. This is annoying but can usually be resolved by simply quitting these apps. My question is; why does this occur? I see no reason for these applications to be using the disk? I haven't found a conclusive response to this question anywhere, always different suggestions/ideas/solutions? Does someone actually know what is causing this behavior and if it can be resolved "permanently"?
On the occasional time, quitting the applications suggested to use the drive doesn't allow me to eject the disc. It is still in use, but no apps are listed and the only way to eject is forcefully. I have tried:
sudo lsof | grep -i <filename>
And yes, I had some interesting results. Although spotlight is not indicating indexing in progress i see that spotlight is using the drive. I know you can add the drive under privacy in spotlight preferences and this eliminates this issue. But there is also "keychain access" using some file on the drive? I just cannot see why this would happen? When this happens, there is no way to safely remove the drive. I have tried relaunching finder, both through dock (ctrloptionmouse click) and terminal (killall Finder), but this does not resolve the eject issue. I have also tried stoping and relaunching SystemUIServer which was suggested somewhere, but this did not resolve the issue. Neither did umount volume or hdiutil eject /Volumes/GusExt/, it only works with -force which I would like to avoid.
Why would anything BUT spotlight use anything on the hard drive? And is there a way to safely kill any and every process using the external drive so that it can be ejected safely?
I find this interesting since it seems to be a common phenomenon but I haven't found a single clear cut explanation or solution to these issues? What makes it more interesting is that I, at home, have my own personal WD external drive with photos and my CD collection stored on it. This drive is NTFS-3G formatted through MACFUSE and NTFS-3G. This drive has never exhibited the same behavior, the only difference between the discs, except the file system, is that the LaCie contains time machine backups. But since I do not have time machine active, I don't see why this would effect the unmount process.
Another topic I would like some feedback on is corrupted files. When this occurs on a NTFS formated disk used on mac, these cannot be removed. And since Mac and NTFS doesn't play nice, I haven't found a way to resolve this. Disk utility wont work, neither will ntfsfix. The only way around this that I have found is plugging the drive into a windows machine and running chkdsk X: -F
Is there any available alternative for this on Mac that actually works with NTFS disks?
Hoping for some interesting feedback on this from anyone interested
Best Regards
Gus

Hi again Kappy. Thanks for your reply.
1. No, none of the files on the drive are being sent by mail, mail should not have any interest whatsoever in the drive.
2. Most files are created by AMBER 10 and AMBERTOOLS 1.4, molecular dynamics simulation packages. These are UNIX based and I only work with these files from terminal, no GUI. They are created on different servers, downloaded to my MBP and transferred (at least most often) to the LaCie for storage.
3. I have applications stored on the drive through "time machine backups", but I do not run any apps from the drive. Only locally on my MBP, all terminal based UNIX programs are "pathed" correctly to my internal drive.
4. As above, time machine backups my apps, but to my knowledge should not run them from the LaCie drive! Only from my local drive...
5. Disk permissions are full read and write for all. Some files come from /usr/local/ and are specific for my account. But I have taken the habit of "chmod 777" them so I can always access them since I'm the only one with physical access to the LaCie drive.
6. It has at some point, I see no indication of indexing being made in OS X, only through "lsof" where I usually can see spotlight and keychain accessing files. But I have now put the drive under "privacy" from spotlight so it should not index at all now.
7. Yes, once a week a manually perform a time machine backup of my local drive onto the LaCie. Between backups I disable time machine.
8. nine times out of ten I can eject the disc without warning if I first quit mail, iTunes and safari. Same goes if I get the warning, exit the app and then try to eject again. One time out of ten it doesn't seem to matter if I quit all the apps except finder, and ever relaunch finder. Some undetermined apps is still claimed to use the drive. Then the only solution of to force eject.
Best regards
Gus

External hard drive unmounts in clamshell mode

I just bought a 13" macbook pro and 24" cinema display. With the mbp in clamshell mode the display comes on, but for some reason the two external drives that are plugged into the back of the display unmount with no warning, flashing an error message. Then they won't mount, and if I reset them they unmount within seconds, again flashing the error message. The rf mouse that is also plugged into the back of the display works without a hitch. What gives? Anyone?
Thanks,
jdv

Any more info on this? I also want to get this monitor and have my external HD attached to it.

USB drives (External) keep unmounting

Hi
Over the past month I have noticed that the two USB HDs I have attached to the two USB 2 ports on my MacBook keep unmounting themselves for no reason.
There is no real reason, just does it. They remount themselves and then unmount, etc.
One is powered through the computer, the other externally.
Can anyone answer this riddle, or suggest a utility that can test the ports properly to see if there is a reason that both unmount at the same time?
Thanks in advance
Rob

It is possible that only one of your drives is causing the whole problem. May I suggest you test each external drive separately for a few days, and see if the behaviour changes. i.e. unplug one drive and compute as usual. Then repeat with the other drive.
The possible outcomes are:
1. Nothing changes, i.e. each drive causes the problem you have previously described.
2. One drive causes a problem, the other does not.
3. Both drives work fine by themselves.
TechTool Pro will test your hardware, including the ports.

911... Unable to unmount disk! My external drive is 499G, the available space is 73G and it's empty!

Hello dear support community,
It all started when few weeks ago I plugged my external drive and nothing from the data would open. Then I got mad and never used it again. Now few days ago, when I plugged it into my Mac OS X Yosemite 10.10 it just went crazy! The full capacity is 499G. I go to "get info" and the available capacity is 73 and the external drive is empty. I have movies and videos of the capacity of 425G. Where did all that information go? I am sure I did not delete any of its content. I even copied the disk on my desktop but I can't open it either. It tell me: "you don't have the permission to see its content" And Also why when I go to "disk utility" to erase or repair the external disk, it shows me "unable to unmount disk" I would like to know what I shall do please! The Files are empty and I want to be able to recover my data and use the disk like I used to. Oh by the way, when I clicked in verify, it told me: "disk needs to be repaired" and that didn't work either.
Thank you for kindly help!
Regards!

Restart. That should free whatever it's showing as an open file.

External Drive Unmounting?

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