Backup an external SSD

You can try rebuilding the Spotlight indexing database to see if that helps.

- Pie Lover

I also use CarbonCopyCloner (bombich.com, $40). It knows Mac systems well enough to properly manage even specially formatted TimeMachine drives. With CCC you can plug data disk and another external drive, and tell CCC to clone your data disk to a "data disk clone". Since I mentioned TimeMachine, CCC can clone your TM drive to another TM drive (perhaps if you move to a larger TM drive?) because CCC recognizes the TM markers.

CCC is also a good backup for your internal drive and creates a fully functional copy of your internal to work off in case your internal suffers a sudden issue at an inconvenient time.

Extra note about CCC ... CCC keeps "old copies" of items it transfers as the backups continue over time. With CCC you can have a rolling history of your data. Just buy a larger "data disk clone" than your data disk for the historical copies.

What is the format of the external drive you want to back up? Time Machine won't be able to backup up certain formats, such as Ex-FAT or possibly others. Many external drives come by default in those PC-type formats and would need to be reformatted for Mac use if you want to be able to backup them up with Time Machine. If it is in HFS+/GUID or APFS/GUID then Time Machine can back it up.

Backups should be dedicated drives. TM wants to dominate the drive for protection of your data. CCC will duplicate the formatting of the drive being cloned (internal or external).

When making a new backup disk, let the backup application take over and after that use the drive only for backups.

I said that CCC can duplicate your external TM to a new drive outside of the computer. I did this once when moving TM to a larger drive, else I would not suggest it was possible (rule of this forum ... do not suggest as a good solution unless you know or in good faith believe it works).

I was just saying that CCC is smart enough to recognize a TM drive and treat it with special care.

Well, I would have advised using a different drive for CCC than for TM ... backups are disaster recovery and are best spread across different devices.

But you have CCC and are learning it, so that is progress. So I will say ... you are welcome.

I do not believe CCC can clone your TM drive per the attached:

https://bombich.com/kb/ccc6/can-i-use-carbon-copy-cloner-clone-time-machine-backup