macOS 12.6.3 Monterey unmounting external drives

Hey therediguana,

We can certainly understand the concern if your external drive is unmounting. We’ll be happy to help out.

To start, go to  > System Preferences > Battery and let us know if you have “Put hard disks to sleep when possible” enabled or not.

Also, disconnect all drives from your MacBook Pro and boot into macOS recovery as outlined here: Use macOS Recovery on an Intel-based Mac - Apple Support

Once there, complete these steps:

1. In the Disk Utility app  on your Mac, choose View > Show All Devices and connect your affected drive.
2. If Disk Utility isn’t open, click the Launchpad icon  in the Dock, type Disk Utility in the Search field, then click the Disk Utility icon .
3. Note: If you’re checking your startup disk or startup volume, restart your computer in macOS Recovery. See the Apple Support article About macOS Recovery on Intel-based Mac computers. Next, select Disk Utility in the macOS Recovery window, then click Continue. If you check your startup volume (Macintosh HD), make sure you also check your data volume (Macintosh HD - Data).
4. In the sidebar, select a volume, then click the First Aid button .
5. In the First Aid dialog, click Run, then follow the onscreen instructions.
6. When the First Aid process is complete, click Done.
7. Repeat steps 2 through 4 for each volume on the storage device.
8. In the sidebar, select a container, then click the First Aid button .
9. In the First Aid dialog, click Run, then follow the onscreen instructions.
10. When the First Aid process is complete, click Done.
11. Repeat steps 6 through 8 for each container on the storage device.
12. In the sidebar, select the storage device, then click the First Aid button .
13. In the First Aid dialog, click Run, then follow the onscreen instructions.
14. When the First Aid process is complete, click Done.

This is further outlined here: Repair a storage device in Disk Utility on Mac - Apple Support

If all items pass, eject and disconnect the drive.

If still unable to isolate things further, test in a new user account and let us know the results.

We hope this helps out and look forward to hearing the results.

Take care!