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How to resolve Mac error ‘repairing disk failed with error could not unmount disk’?

Macintosh systems include the feature to divide hard drive into number of volumes & this enables user manage their critical data in much easy & efficient manner. Among the volumes so created one is the startup volume and other volumes primarily comprising of data are non-startup volumes. The operating system is also contained within the startup volume and it is with the help of this the system boots. Both the volumes are important as one contains the OS and the other one comprises of data.

When issues are encountered with non-startup volumes, commonly referred to as Unmountable volume the volume contained data could not be accessed. In addition to that ‘could not unmount disk’ & ‘disk repaired failed’ etc error are shown. The situation leads to critical data loss & other problems with usual working of the system.

As instances of logical corruption & damage in Mac OS X system is quite frequent, every now & then errors are encountered and to fix those it is recommended using disk utility. The utility is meant for checking the drive integrity & consistency and also resolves minor issues encountered in the process. But, for issues with Unmountable mac volumes, the utility may not work & the very error would keep on taking place.

In a particular scenario, like this when using disk utility to verify & fix non-startup system Mac OS X volume the process seems to have started but very soon after that it stops unexpectedly. This could be ensured, as it shows the below given error message at that time –

Repairing disk failed with error. Could not unmount disk

Further disk utility console, shows the following message –

Verify and Repair disk “Storage”

The disk “Storage” could not be unmounted

Could not unmount disk for verification

Repairing disk failed with error. Could not unmount disk

In critical situations system may become almost unresponsive and returns to its normal state after some time.

Corrupt file system & damaged data structure are most obvious reason behind the issue. So, it is important for the user to verify which files & directory are open & is to be repaired. Again determining this may not be much easy & instead of this a simple reboot will do the work. After the system boots try to mount hard drive & once this happens system occurring issue is resolved.

If the 'could not mount disk' issue does not get fixed this way, the data from Unmountable mac volume need to be recovered using effective & advanced data recovery Mac software. The application does thorough drive scanning for locating files from the drive volumes & safely restores them onto the location specified.