Since Upgrade to Monterey Problem with External Disks

I upgraded to Monterey in Dec. Running MBP 2020 13". Since I upgraded, it takes a couple of hours for my Lacie SSD to mount. Disk Utilities sees it right away. If I leave it connected, TM will do a backup - just takes a long time. Fails at end of First Aid - I think because it won’t mount. Don’t have a problem with Hard Drive mounting right away. Same problem on my wife’s computer and SSD (same model of both). Anyone else experience this and know a fix? I just got a Samsung T7 SSD and it mounts right away. I also notice that Disk Utilities takes longer than normal to show the disks (including internal SSD) that are connected. I saw matt gingerbreadman had what appeared to be the same problem after upgrade to Monterey. Advice? Tried Lacie and they wanted me to erase. But it mounts and does a B/U - just takes a long time to mount.

Is it encrypted? There appears to be a bug in Monterey where encrypted APFS volumes with passcode stored in keychain do not get properly mounted on connect.

I don’t believe my issue is the same, as my volume (not really a disk) is not on an SSD and is located in a NAS that is (supposed to be?) permanently mounted over SMB thanks to Bonjour. I only use it for Time Machine backups.

Mine isn’t encrypted, it’s a sparse image at the end of the day, but does require authentication to mount.

I’m not addressing your issue of TM taking a long time, but I can tell you why First Aid fails on an external drive. As of early this month Disk Utility/First Aid still couldn’t run on external APFS formatted drives (I haven’t checked since I installed the most recent Monterey update, but I haven’t seen any discussion of it being fixed yet). I posted more info in one of the Apple Discussion groups here.

What happens if you try force-quitting Finder?

DiskUtility’s first aid fails on APFS drives because it thinks that it cannot unmount them. It’ a well documented bug. The good news is that you can instead use the command line equivalent (fsck_apfs) to run the check on a previously unmounted disk. Instructions in Howard’s great article below.