I installed Catalina 2 days ago and now my 2019 iMac is very slow, click to open an app, wait 4 or 5 seconds and nothing happens, then the spinning rainbow wheel of death appears for a few more seconds, then the app opens. This evens happens when opening System Preferences or Activity Monitor. I have restarted multiple times and the iMac has been left shut down for a few hours before restarting.
iMac Line (2012 and Later)
Late 2013 21.5" iMac, 8 GB Ram, 1TB HDD. After update to Catalina 10.15.1, the thing was turning into a brick. Nothing worked, Office 365 took 3-4 attempts to launch and only did so after 10 minutes. Chrome, Firefox, Safari were crashing continuously. Creative Cloud, Photoshop, Lightroom, a nightmare. Performance was slow and buggy across the board. Wanted to throw the thing out of the window but, being stubborn, decided that no machine and some crappy software were going to beat me. The age of Terminator ain't not quite here yet. Started in Safe Mode, suddenly everything worked, like a gazelle compared to a Soviet agricultural tractor of the 1950s. It wasn't a matter of CPU or Memory usage, which were all well within the green. Here's what worked for me:
In System Preferences:
Turned off Siri, since I don't use it.
Turned off font smoothing and dynamic desktop.
Removed most of the extensions that I wasn't using anyway, almost 90% of them.
Turned off Notifications for all the things that I didn't care to know about in real time.
Made sure that there were no unneeded Login Items under the User and Group preferences (which in my case were none).
Changed the DNS servers in my WiFi connection to Cloudflare's faster ones (1.1.1.1, 1.0.0.1 and their IPv6 equivalents).
This improved things somewhat, but it was still not performing as expected.
Then:
Removed all the Adobe and Creative Cloud processes that were running in the background and prevented them from launching at login in the first place by deleting all Adobe launchers in HD/Library/LaunchDaemons, HD/Library/LaunchAgents and usr/Library/LaunchAgents. That did it. Restart, and suddenly everything worked. The Verifying App dialog now takes 2-3 minutes instead of an hour, Office 365 launches in 20 seconds, all three browsers launch in seconds as well. Adobe apparently is not yet fully compatible with Catalina and just messes everything up in the background. Will use GIMP for the time being. If I have to use Photoshop or Lightroom for some reason, will have to do a quick file cleanup afterwards - like cleaning up after your dog. Now the birds are out, the sun shines, and I feel like a better human being. Hope this helps!
My iMac has also slowed down a lot . My Mac mini seems to run the same. I also noticed I have to to a reboot everyday because now memory usage pegs out after about 24 hours running .
I think its the mail app causing this
Thanks so much for this. Removed AVG antivirus and it’s running perfectly. Installed Avast antivirus and it’s still all good. Used AVG for years without issue but it just didn’t let Catalina function. My Mac was minutes away from going through the window 🙂
Thank you so much!! Removing all of the Adobe stuff really seems to have worked! I've tried to turn their stuff off before but the horrid things would always pop up on my processes. This explains why the iMac, even when it was new, seemed to slow ... adobe ...even if adobe isn't fully compatible, for me it seems to have been the primary reason that my iMac was running slow and sluggish. Thank you for telling me what the 'coffee' was :)
Funny thing is..
When I purchased new iMac 2 weeks ago, Catalina was already installed as factory condition and my computer was working extremely fast, even with multiple programs open.
Then, after 2-3 days, I get an update notification to Catalina from Apple. I thought "why"?? update again to Catalina when my computer is already updated to Catalina. I thought this was little odd. I thought Apple might have added new features to this another Catalina update, so I updated it. Then, MY ALL OF MY DEVICES (MacBook Pro, iPad Pro, iMac, Older iPad, Including Samsung Galaxy Tab) SLOWED DOWN EXTREMELY. I was like "Whoa!! what is going on!!!" I have been using MacBook Pro for a year and I open multiple programs at once and it never ever slowed down!!! I am definitely sure Apple sends a bug along with this update so that memory card or battery slows down greatly. This was their strategy with iPhones in previous years and Apple got sued and had to pay fines. For iMac, I am only using internet and no other programs open and it slowed down right after installing this new update !!! This is definitely a bug !!!
If Music is running in this mix see relevant post here. That will be likely cause.
iMac slow after Catalina instal.
