Empty the trash

Your Mac is deleting 900 GB of files of all different sizes. Depending on the speed of your external drive and the size of the 120,000 items being deleted, it sounds like your Mac may have days left to go before it is completed emptying the trash.

To be clear, everything is likely functioning as intended -- reading and re-writing large amounts of data on a hard drive can take a long time.

I too found out that moving large amounts of data to the Trash can take forever to empty. A better alternative would be to simply reformat the disk and start over. Reformatting only takes a few moments.

Staynavytom wrote:

That's what I'm doing. Why should I not be doing that? I'm not paranoid about losing backup data.

In that case, you should remove the drive from Time Machine Settings, reformat the drive, re-add the drive and start a new backup. Then your Trash will be empty in moments rather than "over a day".

Another recommendation, never use a drive for Data and Time Machine backups.

As far as your other question, I have never used a drive for both data and Time Machine, nor have I tried deleting Time Machine backup files using the Trash. Not in 30+ years. So I can only guess they will eventually be deleted. I can't say how long it will take.

If you are relying on iCloud as a backup, you will eventually find that doing so caused you to loose valuable data. iCloud is NOT a backup service for Macs. It is designed for cross platform sharing, not for backing up, although it does have some of those characteristics.

FWIW, you should never try to delete files from a Time Machine backup if that's what you're doing.

Since I've never done what you are attempting to do I can only guess. Perhaps someone else will know.

Did you not read my comment above? If you are using iCloud for your backup, your data WILL be lost.