Catalina on iMac slowdown/unresponsive issue

[beachBOYken]

Hi

Have a late 2013 iMac that occasionally (4 times so far on Catalina) goes into a complete state of unresponsiveness.

When it happens I begin to notice it while browsing Safari, it happened earlier while I was on this forum, I could tell something was up as drop down menus/tabs didn't work like they should, and clicking on things stopped working.

Its weird because the more things I try the worse it gets, it doesn't just effect Safari, mail was not opening, I couldn't put the iMac to sleep by placing cursor in bottom corner, and clicking on apple menu to restart, did not open the menu.

Just everything stops responding to my commands.

I have to force restart to get it working again.

I have latest Catalina OS, my iMac has 16gb of ram and SSD drive if that helps.

I don't run any intensive tasks either just safari and mail that are normally open.

Thanks for any help.

 

[beachBOYken]

I'd start with running Apple Diagnostics: https://support.apple.com/en-gb/HT202731
Then maybe an SMC reset: https://support.apple.com/en-gb/HT201295
Then run a disk healthcheck on the SSD: https://support.apple.com/en-gb/guide/disk-utility/dskutl1040/19.0/mac/10.15

Thank you, I will try the 1st and 3rd links to see if that finds anything first.
About the Apple diognostic test it says to disconnect external devices, would that include my time machine backup which is on an external hdd.

thanks again

 

[beachBOYken]

Yes, I would disconnect that before running the diag.

I did the diagnostic test and health check on the startup disc (both volumes), all reported fine.

In the disc utility I had something called disc image volume (mac OS base system), never seen that before, wasn't sure what it was? so didn't run test on that.