Thanks for the clarification. I was going to transition to the new method since even though it may be awhile, I have about 22TB of data to backup. That's about 6 months of backup time. And since it's only going to grow, there is no time like the present. Your other assumptions are correct, so I'll get some performance improvement but not necessarily much.

As a second question that I should have asked. Is there an issue with a never ending set of incremental backups against a primary full or does it not really matter? Or to ask the question another way, is there a rule of thumb for how often a full backup MUST be run. The vast majority of my files don't change. I've split the backups into a couple of jobs. The more often changing ones (and hence the ones where I could run a full backup more often) are also the smallest. So my thinking was that the more often changing ones would have a new full every year while the less changing one would maybe never have another full (or maybe ever two or three years). Thoughts?

I did find entries in the logs but it only points back to a SVCHOST program and a PID that I can't trace back. I tried today to duplicate the issue but failed. I was able to cause it to occur in the past. Unfortunately, there was some Windows maintenance applied as well. Let's just close this and I'll resubmit if it happens again and I can duplicate it easily. Thanks for your support.

I'll check my logs. I found it strange as well that it happened just after DST was changed. I have five other computers in the house that have not had the symptom. Thanks for the great support as always. I'll post what I find or don't find.

Actually, same problem occurred on Windows 10. I thought about taking off a couple of months of Windows maintenance to see if it would make the problem go away, but didn't do it.

It's windows Pro 11 21H2, physical machine. I had looked at that article before and tried it's solution but it didn't seem to change anything. Odd item is that it seems to occur only if there is a very long (i.e. > 15 minutes) between the time that the scan for changes starts and the first file is found.

Dropped back to 5.9.3.26 and it seems to work fine. Just an FYI

Standard system account. It used to work fine. Had always used it in the past. I hadn't done a backup in a few months. All other functions work fine accessing the networked drives. I did try to change the system account but got an unknown failure. Tried it also in admin mode.