iMac keeps crashing after Catalina upgrade

I may have found a solution for the 2018 iMac Pro. I performed a clean install using internet recovery. Fresh Catalina and upgraded to the latest version, 10.15.1. I unplugged all my cables and let the iMac sit for 30 mins. Then added my external thunderbolt displays one by one and my external drives. I disabled sleep and energy saver settings and it seems to be working. It ran the screen saver all night and woke promptly by tapping the space bar this morning. I am hoping that by only running 64-bit apps now it will run smoothly.

Finally rolled back to Mojave.

Clean installs only helped for a while. I'm not using external monitors, just a Wacom Intuos Pro (oldie) and an external SSD. Nothing else. MacBook crashed every single time I closed the lid and quite often when just using the MacBook.

Just know that when you do a rollback to Mojave and restore from a Catalina TM backup, you'll need to change the file extension from your TM backup to .sparsebundle as Apple introduced a new file extension in Catalina for TM backups (.backupbundle). Oh, and you can't use Safari anymore after the rollback (at least, if you've upgraded to version 12). And... You can't use your Photo's library anymore as it was converted to a new structure (I guess it's a new structure).

At least the crashes are gone...

I know it seems weird, but this actually worked. I thought the problem was with my external monitors, which it was but with one caveat. One monitor worked fine, I would get crashes with both monitors connected.

It seems like a race condition with some internal processes and the turning off of the monitors as if I change this to 3 hours, it will crash. I keep it at something like 30 minutes and it wakes up fine. The tick for preventing the HD from sleeping works either way.

Ofc, I reset the SMC and NVRAM multiple times. My monitors are connected via USB-C and USB-C to display port. They are 4k LG monitors. Even though this is just setting, give it a try. It gave me a working config that I could then further test what is happening. I can still produce the crashing by changing this to 3 hours, which is why I believe there is an order of precedence in the settings.

My experience - Was on Mojave. Did a full Time Machine backup, then immediately upgraded to Catalina 10.15.1. On day one, started having the crash issues nonstop - 2018 MacBook Pro completly unusable all of a sudden.

Called Apple Support and we went down a half dozen rabbit holes NOT associated with the issue - 75 minute call. Ended the call right where I started - with a buggy, broke operating system (e.g. Catalina).

Found this video (link below) on how do downgrade back to Mojave - completed all steps. Then, restored my previous Time Machine backup and my problems mysteriously WENT AWAY with everything right back the way it was before I upgraded! Have been going for almost a week on the Mojave downgrade and not a single crash, bug or blink!

I'm seeing folks getting hardware damage, needing hundreds of dollars in repair at Genius, etc. It's quite simple really - DON'T upgrade to Catalina if you haven't yet. It's seriously a hot mess of half baked code. I feel bad for those out there who have had irreversible damage to their hardware as a result of this negligible upgrade push by Apple.

Watch this video to properly downgrade to Mojave: https://www.youtube.com/watch?v=plgOsDEhgqE

A lot of people seem to suggest (and think) that turning off Energy saving completely would prevent the hang / crash. In fact, it's the exact opposite. The kernel is panicking *because* something's hanging on to the display driver and preventing the machine from idling. For me, simply setting "Turn display off after" to "3 minutes" has fixed it. And unchecking "Prevent computer from sleeping.." as well. This way, the kernel no longer panics since it's able to receive 'check-in' sooner.

Try turning all energy saver/eco setting off in the Energy Saver preferences pane.

Set it to Prevent Computer from Sleeping, uncheck put HD to sleep, uncheck enable power nap.

See what happens. That fixed my Catalina KP issues. I have a 3rd party SSD installed in my iMac and somehow it didn't like the whole 'wake from sleep' thing. Not a great long term solution obviously but better than nothing for now.

I just wanted to sound off one more time on this. The two settings I made(Which will eventually kill my mac) are to disable the hard disk from ever going to sleep and stop the monitors from ever going to sleep Since doing that I went to multiple crashes per hour to no crashes for over a week.

Obviously having your hard disk never sleep will drastically shorten the life of your drive unless you shut down your computer often.

Yes this is a flaw with the Catilina update, yes Apple may or may not fix the issue. Depends on how much attention is brought to the issue. Yes It sucks, thats how business works. Post the issue on social media everywhere if you want a reaction. Do it responsible like a grown adult.

Here is what I would recommend.

"I upgraded my Mac to the latest operating system, and it has been plagued with crashes ever since. Research on the web has shown this is a pretty wide spread. See this apple thread for some examples https://discussions.apple.com/thread/250717203. I hope Apple who has been responsible in the past addresses this issue soon. I would stay away from Apple products for now, and if you own an apple product, don't do any updates until Apple addresses this issue"

Settings That Allowed my mac to stop crashing - your hard drive will not last as long, so Time Machine is your friend.

After hours with Apple support, removing memory, PRAM, SMC, deleting non Apple extensions, and full reinstall, I can confidently say that as a software engineer, this is somewhere in the core display drivers. When working with a single iMac screen, no crashes, adding my two 4k monitors, no matter what power or bluetooth settings, the machine will still kernel panic.

After talking with Apple, there are two things very clear.

1. They are aware of the issue and they make you go through the same troubleshooting steps as normal issues. There is not yet a solution and they will not admit it is related to multiple monitors.
2. They do not read, care and nor will they reference or acknowledge these forums. 3 separate times the forums were dismissed with disgust and I found the support experience very unprofessional. Certainly not according to the Apple protocol.

---- Again, if you are having these issue, please attempt to disconnect the multiple monitors and leave the machine overnight. Post your results. --

---My kernel panic issue--

panic(cpu 6 caller 0xffffff7f8f868ad5): userspace watchdog timeout: no successful checkins from com.apple.WindowServer in 140 seconds

service: com.apple.logd, total successful checkins since load (3580 seconds ago): 359, last successful checkin: 0 seconds ago

service: com.apple.WindowServer, total successful checkins since load (3550 seconds ago): 332, last successful checkin: 140 seconds ago

possible fix for some crashes. my computer is 2019 i9 iMac with Vega48, and 2tb ssd. stock with 8 gigs ram . I added 32 gig timetec ram for 40 gigs total. I could get it to crash just by doing multiple export actions in LR. I could select a folder and export all then select 2nd folder and export. and would crash almost instantly. well tonight I removed the after market ram and I was able to export/resize 3 different folders each with 800-1000 pics and it did not crash. ill leave it like this for a while and see if I can make it crash.

I have a Macbook Pro 2015 connected with an Apple Thunderbolt display. Since the time i upgraded to Catalina I was facing the exact same issues. I disconnected the monitor. I had fewer restarts but still... I couldn't work. After 3 horrible weeks, I found a very effective solution!

Go to Apple / System Preferences / Accessibility / Display and untick all the boxes!

It worked perfectly for me. I even connected my screen again and for 2 days now I'm not facing any restart issue!

I had the same crash after the upgrade to Catalina.

I had external monitors using thunderbolt to HDMI cable. The crashes started when I upgraded.

I noticed it didn’t crash if I disconnect the external monitors so I guessed it’s from those cables. finally spent a lot of money on new thunderbolt to HDMI adapters from Moshi. I also bought even a more expensive one from

belkin but which was faulty.

no crash for the past few days. Used to be 4-6 times per days.

PS: looks like Apple wants to keep out accessories producers from providing cheaper, sometimes better, options.

The solutions has already been posted a few times but it’s getting lost in all the unnecessary replies or repeat of the same question.

the solutions is: Disable sleep mode of your Mac 🖥 💻

System Preference > Energy & Saver > computer Sleep set to never and untick put hard disk to sleep.

done that and my Mac mini has been running for a week without crash.

You can go back but it’s going to take a full day or 2 to downgrade to Mojave and a lot of it will be manually installing the apps you had.

heres how I did it:

• First you need to make a time machine back up of your drive (very important!!!). Use an external drive to make one.
• make a bootable Mojave install on a thumb drive. There are YouTube tutorials on how to do this. IT WILL WIPE ALL YOUR DATA AND DO A FRESH INSTALL OF MOJAVE
• next you need to reinstall all of your apps manually.
• You can also copy files and data from inside the time machine image by looking inside it using finder. So copy over user data like pictures, music, documents.
• You can also copy other user data from the time machine image like user settings and app content.
• Finally relax knowing this ******** of an OS (Catalina) is behind you.

Im back running Mojave for a week now and haven’t had 1 single crash, plus my Macbook is a lot less cluttered after having had it for a couple of years now, so it actually runs faster :-)

I went back to Mojave in one day without having the previous system backed up.

I made a Time Machine backup of my broken Catalina install and then clean installed Mojave after reformatting my fusion drive back to HFS. I used migration assistant to move all my applications and settings back. There was very little manual work involved since the installer gives you the option to migrate your data as part of the process.

The only thing I had to reinstall was my printer driver.

I won't be putting back Catalina any time soon.

I had regular system crashes, usually within 15minutes of boot. This only happen when using an external monitor connected with an HDMI cable and Apple's USB-C Digital AV Multiport Adapter.

I bought a USB-C to DisplayPort cable off of amazon for <$20 (cable matters). Using this new cable I have not had any crashes.