Software Update is still checking for updates after Big Sur 11.6.3 yesterday.

Sapote Said:

"Software Update is still checking for updates after Big Sur 11.6.3 yesterday.: Update: I tried Safe Boot Mode again and it did not work. But after restarting in normal boot mode it finally worked. I guess second time is the charm."

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Great to hear! Excellent job troubleshooting.

Haven't tried safe boot, Recovery seemed quicker.

It's 34+ hours now and still good. Despite me booting to another disk with Big Sur on it (my Drobo devices won't work in BS, Drobo wanted a bit more info, it's a 'known issue' apparently, they are working with Apple to fix it I believe).

Anyway 34+ hours and about 4 reboots later and all is still well.

I tried a lot of other possible solutions and nothing stuck, the best I got was 2-3 hours and then it gave up.

I created a keyboard maestro macro to check every hour and let me know if it works or not, every now and then I double check via the system preferences.

I *think* that clearing out that install.plist might have been the key for me. It seems to hold a list of updates to apply, but there were no directories for them so it could never complete.

Anyway, I searched for a few days, tried quite a lot of things that worked for other people, none of which worked for me. My issue only started after installing the 2022-02 patch, if I undid that, (initially via time machine, 2nd time via a CCC clone, 3rd time I did a clean reinstall and a migrate), each time it worked until I applied the patch, immediately after the reboot then the problem appeared!

I decided to clear out those directories just on the off chance, I had backups so it was worth a shot and thankfully, so far, has worked.

Fingers crossed it might fix it for you too.

Also, how long has the slowdown been going?

You know that after an update macOS does quite a bit of housekeeping and the machine crawls for quite a while - at least mine does!

It verifies all the applications, rebuilds caches, xpc, dyld etc etc.

Can't guarantee it will fix it, but it is worth a shot, it clears out all the crud, rebuilds all the necessary stuff and should hopefully make things better.

If it doesn't then back to plan A and do a clean install.

Hopefully something will fix it though.

I wished I could have stayed on High Sierra, but Apple make that very difficult. I've been using Macs for 30+ years and they get worse with each update. The only saving grace is that it isn't Windows 😉

Expect an Other… in the Software Update panel for Safari 15.3 which trails the 11.6.3 release by a few hours.