The disk identifiers used in commands can be found by running 'diskutil list' in the Terminal, and then checking these locations in the command's output. There are a number of third-party tools out there that can rebuild and otherwise manage a faulty drive, but Apple also supplies tools other than Disk Utility that will work. Sometimes secondary tools and approaches can at least modify the partition table enough to allow Disk Utility to overcome its hangup and work properly. If when attempting to repartition a disk you are met with 'resource busy' or 'cannot be unmounted' errors, first try using a different tool than Disk Utility to tackle the job. At other times, the drive may simply be experiencing some partition table troubles or be used in ways that prevents Disk Utility from modifying the tables. Sometimes when errors like this occur, it suggests the drive may be failing however, this is not always the case. Windows are accessing folders on the disk.To partition and format a disk in OS X, you generally open Disk Utility, select the disk in the tool's sidebar, and click use the Partition tab to select and apply a partition scheme however, there may be times when this will not work, and Disk Utility will give you an error such as the disk cannot be unmounted, or that the resource is busy.

Make sure there are no applications currently running from theĭisk you want to initialize.

Alternatively, if you have theįinder set to display disks on the Desktop, you can drag the disk to The left pane of the Finder toolbar window, an eject button shouldĪppear to the right of the disk's listing it looks like an up-facingĪrrow with a line underneath it.

Try to unmount the disk manually from the Finder.

If you are still having trouble unmounting the disk, try the To boot from a CD, DVD, or different hardĭrive, see ARCHIVED: On a Mac, how do I change my startup volume or boot from an You should always boot from a drive other than the one you're trying Initialized if the drive is in use, it cannot be unmounted, and thus A drive must be unmounted or taken offline before it can be This error means that the hard drive can't be unmounted because a file May get an error message about the program being unable to unmount the In Mac OS X, when you attempt to initialize a disk withĭisk Utility or a third-party drive formatting utility, you Information here may no longer be accurate, and links may no longer be available or reliable. This content has been archived, and is no longer maintained by Indiana University.

Os x error could not unmount disk