I have Google Drive running on Mojave with the sync folder locating on an external drive. After a recent reboot, I got a cryptic error message with a link that did not lead to any resolution:

The permissions needed to sync your files have been corrupted. To repair access and launch Drive for desktop, click Learn more.

Google Drive launch error

I couldn’t tell if that was permission errors with the external drive or with the running process. While the error message was displayed, I was able to shift-click on the settings gear icon and choose Generate Diagnostic Info. One of the log files showed a curious error:

CheckIfKextStagingRequiresRepair /private/var/db/KernelExtensionManagement is missing the ‘restricted’ flag

From the drive_fs.txt diagnostic file

The solution to this problem was to set the restricted flag! To do this, I needed to reboot my Mac into Recovery mode, which means holding down the Command-R keys during the reboot until I get to the recovery screens. It prompted me for what language I was working in, and then I went to the Utilities menu and opened the Terminal.

From the Terminal I set the restricted flag using the chflags command. Normally the file/folder to fix lives at /private/var/db, but because I was in recovery mode, that folder was located a little deeper. Here’s where it was for me:

$ cd /Volumes/Macintosh\ HD/private/var/db

I used the ls (list) command to see KernelExtensionManagement in there somewhere. Then I fixed the flags like so:

$ chflags restricted KernelExtensionManagement

I rebooted, and Google Drive worked again. Hope it works for you!