What was in the September 24, 2020 update that killed my iMac?

2 Keys for Restore...

1. Start up from macOS Recovery

To start up from macOS Recovery, turn on your Mac and immediately press and hold ...

Command (⌘)-R

Installs the latest macOS that was installed on your Mac.

Have you tried booting into safe mode?

Try a safe boot.

    Shutdown your machine.  Hold down the shift

key.  Poweron.  The boot up will take longer than normal

because the filesystem on the startup drive is being checked and

repaired as needed.   All about safe mode including what

features and apps safe boot leaves out. 

Safe boot uses a software driver instead

of using your machines video hardware.

http://support.apple.com/kb/ht1455

I read this reply just now:

VikingOSX

User level:

Level 9

(65,581 points)

macOS

Speciality level out of ten: 1

Sep 29, 2020 1:20 PM in response to Starman35

It knocked the socks off my 2014 MacBook Air that was working perfectly with Mojave 10.14.6 before the 2020-005 update. I booted into Recovery and performed a Disk Utility First Aid, rebooted into Safe Boot mode and emptied the entire ~/Library/Caches folder contents, and then rebooted normally. At that time, I emptied the Trash.

Once the above was done, the Air returned to normal functionality, more or less…

I think if we all start a new thread with, say, "Apple Software Update Sept 24 2020 Has Crippled My System", then Apple will maybe respond. So far, discussions are only going under one or two posts. They probably only notice headlines for individual posts, so they probably need to see lots of them.

This is going to sound strange, but my iMac is beginning to behave normally again. I have no idea why this is happening. It's been about 4 hours since I last rebooted. Apps are opening quickly. Pdf's are opening - until about 30 minutes ago I was getting "could not be opened because file does not exist" - now it does. Textedit opens as usual. Games open as usual. Multiple browsers open simultaneously. Two hours ago, all was NUTS. This is the weirdest update I've ever encountered. Maybe my computer is sobering up...? Maybe the system just needs LOTS of time to deal with the update.... As of now, it's running just as it did yesterday. Totally weird....

Well, I spoke too soon. Booted up today and it's been 1 1/2 hour and I'm still waiting for it to open a single email. I'm here today on my phone (android).

What makes the system go bezirk is that it registers each keystroke and click: it just takes about 20 minutes to execute. So if I click too often on something because of no response, each click is cued up to bite me later. For example, a "force quit" that didn't seem to register ends up happening half-hour later. Then Safari suddenly opens (clicked that an hour earlier) . Apps are opening and closing, seemingly at will but it's just because it's SO FFING SLOW.

This is a 2016 system. My old 2007 Tiger iMac is still running beautifully. Instant response. The only reason I bought a new one is because of internet access. Old Safari won't work there anymore. Garageband is better on the 10.4 Tiger. New one is a joke.

Tiger was the best system Apple ever made. From that it's been downhill.

We are used to it. Apple does respond to warnings from volunteers about "inmates" getting out of line and to answer posts that have not gotten answered by us volunteers.

I found your comments "OK".

R

I'm hoping some wizard can help. I have the same problem on my iMac.

... should have said I'm running Mojave 10.14.6 on a Late 2013 iMac with 8GB of RAM

Same here

Apple probably wants everyone to upgrade to Catalina, but that is not an option for me. I'm already with one foot in an other eco system. I think I will leave entirely...

I already posted. Should I delete it?