Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
maybe answering my own question, think it's related to running carbon copy cloner. hmmm, hoped someone here would recognize the message....
 
I see it now shows up as a category in my notifications:

1638871974816.png


I'm not sure why. Maybe from when the disk was almost full?
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.