External disk not ejected

Is your photo library on it?

It could be the external drive it's self or the cable

If the data on it can be backed up to another external drive or back to the Mac I would try reformatting it.

Erase and reformat a storage device in Disk Utility on Mac

Erase and reformat a storage device in Disk Utility on Mac - Apple Support (CA)

This is a backup drive for Carbon Copy Cloner APFS

CCC may have left a lock on it if it is not currently running a backup or some other checks.

I don't know if this is true for regular storage media, but I have found that Flash memory drives don't eject because they are somehow corrupted. Formatting them resolves the problem.

If it is a backup, and nothing is actively writing to it (no Blinky light), just unplug the data cable, dismiss the notification, and plug it back in. The danger of unplugging a drive instead of ejecting is solely due to the possibility of causing an incomplete write. If it's not writing, and several minutes have gone by since the last write, the write cache has most likely completed.

If it gets corrupted, reformat and run another backup. You do have more than one backup, right?

mrokloricred37 wrote:

If I have an external disk which can't be ejected "because one or more programs may be using it".

How do I figure out which program/s are using it so I can stop the program/s (assuming it is appropriate to do so) and eject the volume.

I guess the offender/s are in Activity Monitor, but don't know how to find which one.

In addition, I have put the volume in the Privacy section of Spotlight with no success

I have quit all of my applications as well.

As always,

Thanks

There are credible reports that some Third Party Security Software will interfere with this process of ejecting External Drives

Also, in what Format is the drive ? NTFS for MS Windows ?

I'm having the same problem and it just started after upgrading to Mac OS 15.1 from the latest Mac OS 14.x. I have three SSDs that I alternatively back up to each subsequent evening. I just did an experiment where I plugged in the last drive last updated under 14.x and then ejected it without a problem. I then remounted the SSD, ran Carbon Copy Cloner to update the backup, and now the drive will no longer dismount after running the update without Force Ejecting it. All three are now doing it. If I remount the drive, it seems to be working okay. I don't know if this is an issue with 15.1 or CCC, or both.