iMac keeps crashing after Catalina upgrade

I'm having the same issue. I have successfully stopped (read: worked around) the problem and recreated the problem three times.

I have two 4k monitors attached to my 2019 MacBook Pro (2019 MacBook Pro with 8-core i9 processor and Radeon Pro Vega 20 GPU). It seems that whenever the computer under a heavy computational load (like bulk transferring large files) and engages the GPU to assist, the computer freezes and then force-restarts to resolve the situation. (I'm sure that's not technically what's happening under hood, but that's the best way I can describe what seems to be happening.) This happens only when I am connected to my 4k monitors. When I disconnect them, my MacBook is stable and doesn't crash.

So now have two 4k monitors that are sitting unused until Apple gets this fixed, or I revert back to the previous OS version. This is hands down the worst upgrade experience I have had with Apple since I bought my first Mac in 2007. Disappointing, to say the least.

Issue is with Spotlight mds process.

If you have large folders with lots of files exclude them from Spotlight searching under System Preferences > Spotlight > Privacy.

This fixed my Catalina crashing issue.

What worked for me was to restart the computer in safe mode, remove all devices connected that isn't a monitor mouse and keyboard. Restart the computer back to normal mode, work with the computer without anything connected, if everything works, then connect one device at the time, see work with the computer with only that device connected and see if it crashes, if not you connect the next. That worked for me and hasn't crashed or froze at all today.

Credit to Apple support via twitter, apparently starting in safe mode will clear cache and fix some problems, which it did for me.

Running MacOS Catalina 10.15 on Macbook Pro 11,5 with 2 monitors attached. All software up-to-date and lots of SSD disk space and RAM.

Initially started as a problem highlight text in word for Mac. When I highlight anything in word, MacOS halts for 10 sec. Then I go back to work until I make a mistake and highlight something. Then after a few halts, one of the monitors normally turns all red or yellow sometimes, then back to normal for a short period of time before it outright crashes. Wash, Rinse, Repeat!

Word for Mac solution: When working with word for Mac on Catalina, disconnect all external monitors and all is well! All solutions found online including installing everything all failed.

Now, the problem is beginning to show on Pathfinder 8.6 as well as VLC (2 crashes today!)

Again, the solution, disconnecting the monitors solves the problem!!!

Looking at at the console logs, the problem seems to be related to AMD Graphics.

Hi,

after a week of running with less and less crashes after my fresh install (and maybe I was being more careful). I decided to reset the NVRAM and SMC. Now I am running a week without any random crashed and in the last two days I am have also reinstalled my full set of apps and I have been using my laptop as intense as before.

It seems the problem went away with a combination of cleaning up my old install and the hardware resets. Next time I should directly follow these steps.

I am sorry to hear that other people still have problems and some solutions similar to mine still do not help.

Cheers

Duc

Just following up after seeing these issues continuing.

I've switched off my external pair of Dell monitors for the moment and started using my iPad Pro as a second monitor with Sidecar. It's not ideal, it's not as productive as having multiple monitors but it works and does not crash, so that's a potential interim option for those that have one available.

Let' hope 10.15.3 helps....

Steve

I had exactly the same problem with 2 screens connected in Thundebolt on my iMac2019.

I bought a Thundebolt Elgato dock to which I connected the 2 screens and since then there has been no problem. It seems that it is the management of the 2 Thunderbolt sockets of the iMac that are problematic for Catalina

I have been dealing with this issue on two iMacs with Catalina.

The crash only happens when external monitors are connected.

The only workaround I have been able to make work is NEVER allowing the screen to sleep (screensaver ON) by using the "Amphetamine" app from the App Store. Any combination of settings without using "Amphetamine" cause the kernel panic when the computer idles.

I don't need Paragon anymore

From EtreCheck report:

2020-01-08 09:39:10 Kernel Panic (4 times)
        Details:
            panic(cpu 4 caller 0xffffff800de6520a): Kernel trap at 0xffffff7f8ee30
            473, type 14=page fault, registers:
        3rd party kernel extensions: 
            com.paragon-software.filesystems.ntfs

Fixed my Mac's nightly crashes. I believe it was McAfee's Total Protection scanner. Once uninstalled crashing stopped. I remember support indicating they have a special work around for Catalina. But, yet to attempt reinstall. What I get for deciding to install virus protection after years of going commando.

Hello Praetoriano - I have been able to replicate your problem on two iMacs - crash on idle only when 2 external monitors are connected (Late 2014; iMac Pro) and I have been able to keep the computers awake and avoid kernel panics by using "amphetamine" app from the App Store, and leaving the screens ON, running a screensaver. You must use amphetamine to keep the screens on, however.

Download and run Etrecheck. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Add Text button to include the report in your reply. How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report

IMPORTANT:

Before running Etrecheck assign Full Disk Access to Etrecheck so that it can get additional information from the Console and log files for the report:

ALSO IMPORTANT:

Then we can examine the report and see if we can determine the root of the problem.

It means that Catalina is more sensitive to the quality of the RAM. We have have numerous users come to the ASC with complaints of problems that related to added RAM. In nearly all cases the added RAM was from sources other than Crucial.com and MacSales.com. Both suppliers test their modules in the model they are designed for and guarantee their compatibility.

Many users had no problems with their RAM until the got to Mojave or Catalina and then it all went south. They reported replacing the modules with some from the two suppliers noted above solved their problem.

So I'd say the source is experience.

10.15.3 finally fixed both my Macbook Pro 2019 16 inch and my Macbook Pro 2018 6c Vega 20. They were both suffering from sleep restarts (windowservice timeouts) when connected to 2 4K monitors with one monitor on each machine connected through a thunderbolt 3 hub.

It was the most annoying restart bug in 36 years of using Macs (since the first Mac in 1984). This has been more painful than going to PowerPC or to Intel or to 32-bit everywhere. (moving to 64-bit only in Catalina) - I only had to walk away from the computer. I can only hope this is figured out if/when they move to ARM for some machines. What Apple has to remember is to NOT release software if it is not completely stable. This is the reason we did not use Windows in the first place. We want the ability to not have our creativity interrupted by our operating system. It should just work whether we are creating music, movies, art, books, plays, photographs, or code. Apple please listen to this group of disgruntled users because the pain is real. It is sad when Windows 10 just works and Mac OS does not.

"...“Put hard disks to sleep when possible“ in the energy saver settings.

No panics since I have disabled this option...."

Well done, good deduction. That setting is pretty unnecessary these days and well worth trying with it it off