Complete freezing occured once or twice a day (everything, even the mouse, and only a hard restart stopped it). Endless beachballing for no reason, locking up of the entire computer upon sending a print task, all printer and scanner data disappeared a few days ago with the printer being unable to be re-added, bursts of noise in the audio system with glitches, app crashes, you name it. Simple tasks that should take 5 minutes take over an hour due to constant freezes, glitches and crashes. I can't even use a web browser without the system completely locking upįor a while (down to the clock stopping). Since then, each day the computer has gotten slower and slower.

I updated my late-2015 21.5' 4K iMac to Mojave last month, due to the release of Catalina (I generally allow some time for new OS updates to stabilize a little before updating, as I use my computer for audio and video work in addition to a basic home computer).