This is a HUGE problem as it hangs up my work. I get the spinning beachball when trying to save something, move a file, open a file, print a file - but other than that, I can watch videos, listen to music, or read an email. Thank heaven I have a MacBook to work around the Finder fail on my iMac (Late-2015, 3.2 GHz Quad-core processor). Yep, Big Sur 11.2.3 is a bust. Have tried Recovery, have reinstalled Big Sur twice, have used CleanMyMac as I always do, have talked to Support (who spent 20 minutes with me on this Apple-created problem, gave me a couple How-To PDF's, and sent me off with a pat on the heinie to solve it on my own. Hey Apple: we need this fix quite urgently in 11.2.4 !!! And that's coming when?