I failed to format a USB flash drive.
It alerts, “The volume on disk4 couldn’t be unmounted because it is in use by process 0 (kernel). Error: -69888: Couldn’t unmount disk.”
Disk Utility reminds me that it is an unwritable disk. Terminal failed to format it, either.
I’ve checked the security settings, no problem.
Now, the drive has even become inaccessible, though it worked yesterday.
Can I access the files on it?
The “couldn’t unmount because it is in use by process 0 (kernel)” error usually shows up when macOS can’t properly communicate with the device anymore. The “unwritable disk” message is also a sign that the controller may have locked itself into read-only mode or is just not responding.
Right-click the drive and select Get Info, scroll to the permissions section to check if this drive is read-only to use.
If it is, click the lock at the bottom, use the admin account and password to change the read-only permission to Read & Write for you.
If that’s not the case, the drive may be corrupted. You could try using a data recovery tool like iBoysoft Data Recovery for Mac to rescue files on this drive.
Download iBoysoft Data Recovery for Mac, install and open it.
Select your drive and click Search for Lost Data.
After scanning, check the files, choose the wanted ones, preview them, and click Recover to save them to a different destination.
If the drive can’t even be detected by iBoysoft Data Recovery for Mac, the drive probably has hardware issues. You need to take it to a recovery lab.