Brand new My Book 4TB not recognised on iMac

Hi there community,

I’ve just purchased a My Book 4TB to set up as the Time Machine drive for my iMac. I plugged it in and selected the drive as the Time Machine drive but the setup process failed giving me a message about failed partitioning (I don’t remember it exactly now sorry!) But now the drive isn’t even visible on my desktop (I tried to unplug and plug in again but nothing changed). In Disk Utility it is visible as an unmounted disk but clicking “Mount” does nothing. Clicking “First Aid” gives me a failure notice with the following details:

Repairing file system.
Volume is already unmounted.
Performing fsck_hfs -fy -x/dev/rdisk5s2
File system check exit code is 8.
Restoring the original state found as unmounted.
File system verify or repair failed.
Operation failed…

I was told that this would be a simple plug in, set up and let Time Machine go type exercise, so help would be much appreciated!! :slight_smile:


Hello cangel,

This issue may be due to the incompatible file format of My Book with Time Machine, as it comes with exFAT file format and Mac Time Machine doesn’t support exFAT to create backup. I would suggest you to install WD Drive Utilities and erase drive with HFS+ file format. This will change its file format into HFS+ which is supported by Mac Time Machine for backup.
Note: Erasing of drive is a data destructive process. So take a backup of important file from My Book before going to backup.

Thanks asp73, the first problem though is that the drive isn’t even showing up anymore so I can’t access it to update or install anything. Any suggestions?