Monterrey MacOS 12.3.1 upgrade causing errors reading external drive used by 3rd party applications

while you cannot access files directly from the app, if you right click a file and do an "Open with..." and select the problem app do the files open?

This could indicate if there is a deep file system issue or an application API issue (Application Programming Interface) that the developers use to access the file system.

Also, is System Preferences->Security & Privacy under "Privacy", check the "Full Disk Access"and "Files and Folders" to see if the apps are properly enabled for external drive access. If they do seem to be enabled, try disabling and ten re-enabling. A preference file may have got borked.

Yes, I've just discovered the same issue running a 27 inch 2020 iMac (3.6 GHz 10-Core Intel Core i9)

I have a WD Elements SE 5TB portable drive that has worked fine up until upgrading to 12.3.1 last week. The drive still mounts and shows in the finder and files are accessible through the finder but when I use other apps to view any files located on the drive it doesn't recognise them.

The apps I've tried are GoPro Quik (not really supported), Adobe Bridge, Illustrator and Premiere Pro, iMovie to name a few.

I've disconnected the drive and hooked it up to my new MacBook Pro 16 inch 2021 (Apple M1 Pro chip) and have had no trouble and am able to access the files using Adobe Bridge. Didn't try others.

Seems to me that the upgrade has messed something up with file permissions on external drives running off older machines.

Although the initial problem is fixed I've run into another issue with the external drive. Waking my computer from sleep mode seems to result in no files being visible on the external drive and I have to restart to be able to see any of the drive's contents.

Do you have the same issue?

After upgrading to Monterey 12.3.1 my external drive is not mounting and is no longer accessible. I was also using that drive as a Time Machine backup. I also tried to upgrade (same day) Photo Mechanic, a 3rd party photo program which I've used and successfully upgraded for years, and the Safari download worked properly but the .dmg file didn't mount in order to complete the upgrade.

Please advise.

What is the format of the drives? NTFS? Encrypted?

No, it's still on 12.2.1 and am now reluctant to update it in case it won't recognise the drive. Hoping for a solution before I do that.

I had the same issues. Found under Security & Privacy - Full Disk Access that the programs have been unticked.

Tick the programs and you should be good :)

Worked a treat! Thanks @TommyTags.

Pays to note that a restart may be required as simply ticking the boxes didn't fix the problem right away for me.