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iMac slow after Catalina instal.

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)

Posted on Oct 11, 2019 5:09 AM

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Posted on Oct 15, 2019 8:29 PM

Even after installing the Supplemental Update my iMac (5K, 27", 3.6 GHz 8-Core Intel Core i9, 64GB DDR4, 3TB Fusion) is still incredibly slower than when I was on Mojave. I mean I used to open like 50 folders in the blink of an eye & now you can literally watch each one open because they take about 1sec each now. It's painfully slow. I even installed fresh with no 3rd party apps at all & it was still painfully slow. There are complaints all over the Internet about the speed. So far, everything I have tried has been futile. There is nothing in the Activity Monitor that's using abnormal CPU usage either making this issue even more odd. I hope they address & fix this soon.

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Oct 15, 2019 8:29 PM in response to TimGsy

Even after installing the Supplemental Update my iMac (5K, 27", 3.6 GHz 8-Core Intel Core i9, 64GB DDR4, 3TB Fusion) is still incredibly slower than when I was on Mojave. I mean I used to open like 50 folders in the blink of an eye & now you can literally watch each one open because they take about 1sec each now. It's painfully slow. I even installed fresh with no 3rd party apps at all & it was still painfully slow. There are complaints all over the Internet about the speed. So far, everything I have tried has been futile. There is nothing in the Activity Monitor that's using abnormal CPU usage either making this issue even more odd. I hope they address & fix this soon.

Nov 7, 2019 2:08 PM in response to TimGsy

I updated my mac os software from Catalina version ?? to Catalina, version 10.15.1. Afterwards, my internet connection was so slow that it was virtually unusable. After spending a day and various attempted fixes, I am happy to say that the issue has been corrected. My speed is now blazing fast! The fix, for me, was to remove my Trend Micro antivirus software. Supposedly, you are not to install an outside or third party Antivirus software on a mac. I am very proud of myself! Roland Ott Jr.


Dec 8, 2019 11:26 AM in response to TimGsy

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!

Oct 11, 2019 5:34 AM in response to TimGsy

Have a look at the memory tab and see what is using memory. My 2015 iMac was running very slowly when RAM was all used because a Swap File on HDD was in use. In my case it was Music but ......

I'd also observe that since sorting the number of issues and using machine it seems to be speeding up further with time which make me wonder about indexing etc.

Sorry, cannot be much more help.

Oct 11, 2019 6:07 AM in response to robby163

I saw the spinning wheel a lot yesterday. Applications seemed a bit laggy to open. I seem to be seeing this less with time and my Mac is feeling more "normal". I have a Fusion drive so another possibility could be that frequently used files are being transferred to the SSD side as they were before. I can definitely say things are improving with time.

Oct 14, 2019 10:41 AM in response to TimGsy

i have a Imac 2019 with ssd and i have some problems too. the boot is very slow: it lasts 33s for the login screen, 42s for complete boot!!! before with mojave it took only 22s for the login screen and 26s for complete boot.

some apps became very slow; opening activity monitor for example needs 5 seconds and the spinning wheel appears.

the ssd become slow too: it lost 400-450Mb/s in reading speed!!

Nov 7, 2019 9:06 AM in response to TimGsy

I have had a Mac since 1989 - the old Classic and System 6 - I can usually troubleshoot but not with Catalina, except for restoring the Dock.

I have tried everything apart from a clean install - reset the PRAM, reset SMC, run Onyx, run CleanmyMac but Catalina is still dreadfully, dreadfully slow on my iBook Pro.

You used to be able to rely on Apple but it is now the new Microsoft releasing buggy software with all their resources going into selling Apps., music and TV.

Nov 7, 2019 11:34 AM in response to Sisti

I agree that the Boot Speed is faster, but this update by absolutely no means addresses the larger issue. I used to be able to open 50 folders in the blink of an eye, now it literally takes 1 second per each folder, so now I wait almost a minute for this task that only took a few seconds previously. It's completely broken. I'm running on a brand new iMac also & have tested in Safe Mode & a brand new user with nothing running in the background. Exact same stupid results. This is completely unacceptable.

Nov 23, 2019 8:12 AM in response to Doren_Sean_Michael

You are right, of course, I just wondered where the information had come from.


I always had Norton Antivirus in the past but I also have Little Snitch and Norton, in their infinite wisdom, decided Little Snitch was also antivirus and I couldn't have two antivirus so wouldn't install.


I had exactly the same problem with Bitdefender so I now have Trend Micro but it really does slow everything down. Maybe it is time to try Sophos if Trend Micro doesn't improve.

iMac slow after Catalina instal.

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