Time Machine keeps reporting found thousands of changes before backing up
I recently "started over" with my Time Machine (TM) backups as I upgraded to Monterey and TM seemed to have problems with the pre-existing TM backup (it just wouldn't back up.) So I started over and the new backup initially worked for about 3-4 backups. And then TM began to hang. So, following the direction of an Apple Support rep, I re-confirmed my drive (in TM) that I was using for backup and it again began working as expected. But now the newest and latest boondoggle is when the backup session begins, TM laboriously reports its finding thousands and thousands of changes, counting seemingly every change one-by-one and the process is taking FOREVER. In this current session, it reporting over 115,000 changes which took over an hour and shows as about 20% in the progress bar. Now its copying files at about 30% done in the progress bar, with 250 megs copied and it estimates about 15 minutes remaining. And we all know Apple time estimates are ALWAYS way off.
I would think this counting of changes would maybe happen once or maybe twice but no, it happens every time TM begins its backup session. I have had Macs for over 30 years, started using TM when it first came out and have used TM backups to restore drives and I've NEVER seen TM be so slow. And this is 2017 iMac, which by the way, is the slowest Mac computer I've ever worked with.
Can anyone tell me why this counting of changes occurs? The only recent change I can account for is the installing of a small software program (17 megs) and a few emails. I have also deleted a couple of large files but certainly TM doesn't see a single deleted 3 gig file as 3,000,000 individual changes? This whole Time Machine backup process is getting old!
BTW, my backup drive is USB 3.0 and formatted to Mac OS Extended with more than 70% of the 2 TB available. Thanks!
iMac, OS X 10.11