(For example to Erase/Partition the disk). Attempt again to perform whichever task caused your ‘Couldn’t Unmount Disk’ error.Also perform a permissions repair if required. Select the ‘First Aid’ tab and verify the troublesome disk, repairing if needed.If you have created your own bootable drive with a full system, open Disk Utility from /Applications/Utilities. If you have used our method above to create a bootable installer, choose ‘Disk Utility’ from the available menu.Then select the desired external drive from the startup manager screen and press the enter key. If you have an external bootable disk, connect this to your Mac and power your Mac up whilst holding down the OPTION/ALT key.Some of the following steps are destructive and will lose ALL data on your drive. I would strongly recommend at this stage attempting to back up any data that is required before proceeding with the following steps. To create your own bootable disk, refer to our blog ‘Creating a Mavericks bootable install disk’. You can then run Disk Utility from there.Īn external drive or a network drive is preferred if it is the internal hard drive you have an issue with, since the OS X Recovery is a partition on the same physical drive which may not be able to successfully unmount or modify your internal disk. So the first thing to do is to startup the Mac from another bootable drive such as an external drive or OS X Recovery. Normally, any ‘Couldn’t Unmount Disk’ error is attributed to circumstances where the boot drive is being modified or is being used by an application or process. This has a 20-30% success rate in my experience.I have found myself recently experiencing a couple of Macs which would not allow me to repair the directory or permissions in Disk Utility, or erase/partition the drive with an error such as: ‘Disc erase failed couldn’t unmount disc’ or ‘Disk Erase failed with the error: Couldn’t unmount disk.’Įven trying to use Network Deployment tools such as Apple’s Netinstall service or DeployStudio have also failed to deploy due to these errors. Either way, as mentioned, prepare for a Genius Bar visit but try reformatting from another media first as it gives unrestricted access to the internal drive. If the greyed out partition still has it's original name (like Macintosh HD) it may not be as serious, if the greyed out partition has a weird name that is not one you set then it may be more severe. I dont know if this will default to the local recovery partition or force an internet connection, maybe Linc can clarify. To do this, boot your Mac holding down the Command and R keys simultanously. If no external boot drives are available then you can also try Internet recovery which basically loads the recovery partition from Apple's server (slow process). Then from there, run disk utility again and see if it allows you to reformat. See if you can boot from another media like an external hard drive with a system clone or a USB drive with an OS X installer on it. While there is definitely a problem, you could be lucky and just have a case of messed up formatting. Is there any way of saving this drive, or this Mac? Thanks in advance.Īs the recovery partition is in fact part a hidden partition on the hard drive you are trying to reformat, this can sometimes create the behavior you describe. I rebooted the computer back into Recovery Mode, tried again, only for the process to repeat itself (albeit with thick gray vertical bars appearing on the screen, and a square made up of thinner gray horizontal lines appearing next to the mouse cursor, during the initial unmounting process!). The process started, with the diagonally-scrolling progress bar sitting at the "Unmounting disk" status for several minutes, only for an error to pop up reading "Disk Erase failed with the error: Couldn't unmount disk." Any further attempts to erase the drive resulted in the same error popping up instantly. I then opened up Disk Utility once again, selected the hard drive (the main boot partition is greyed out in the side menu), and clicked Erase. I booted from the Recovery Partition once again, and attempted to have the OS X Mountain Lion installer format the hard drive, only for the existing boot partition to not show up in the drive choices menu. After several issues, the hard drive started giving the "Incorrect number of threads" error when Disk Utility's Repair Disk was run from within the Recovery Partition, after which, the computer refused to boot normally, going through a 'status bar' for a long time before shutting itself down. I'm dealing with a 15" MacBook Pro (April 2010) which seems to be unwilling to reformat its own hard drive.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |