Since installing Catalina yesterday, multiple crashes from userspace watchdog timeout

Hard to believe that such frequent kernel panics are continuing in Catalina for so long, but I'll add one more data point that might be helpful. I just purchased a new MacBook Air that came with Catalina and then immediately upgraded to 10.15.6. I did not (yet) migrate from my previous MBP or restore a TimeMachine backup. I only just started installing a few apps and configured the system settings. I haven't yet plugged in my external monitors or done much of anything that could be implicated in the kernel panics. Yet they have been happening to me as well -- 4 crashes (due to the same userspace watchdog timeout kernel panic) within the first two days of my purchase. The only thing that might have stressed the system was an attempt to set up TimeMachine to back it up with an external drive plugged into a USB hub. The drive was fairly full with backups from an old MBP. So, I deleted a large number of the old backups and ran "Empty Trash", which chugged away for hours. When I came back later, I noticed that my system had crashed and rebooted. That same scenario repeated several more times before I called Apple Support, who (after probably checking this same community forum thread and similar threads), suggested that I uncheck "Put hard disks to sleep when possible" in the Energy Saver System Preferences. I'm now waiting to see if that does the trick (though if it does, that's still a lousy mitigation option since it will reduce battery life over time if this is never resolved otherwise).

My update: have only seen one crash since 10.15.6. I have a 16" MBP that would crash like clockwork every time the display powered down. Nothing fixed it, not even (a now likely unnecessary) logic board swap. On 10.15.6 that has gone away. I have 64 gig of memory and 7.5 wired and the machine has been up for days. It's running app update, sys prefs, mail, several shells, safari with at least 8 windows and probably 50 tabs, chrome with 15 tabs, ichat, itunes, podcast, ACDsee photo, bbedit, serial tool, and a chat client. I haven't run VMWare since VMware won't run my VMs on this machine, not sure why that is yet. It can't open /dev/vmmon but I have allowed VMware in the security prefs.

Your problem is most likely unrelated to this thread, but what version of macOS are you using?

Apple menu -> About This Mac

It really looks like a graphics hardware and/or software related issue to me. The ”dot” system updates for macOS usually contain graphics driver updates, so in that sense it's always good to install the latest update for the macOS version one is using.

Also, try to run the hardware diagnostics and see if that comes up with anything:

https://support.apple.com/en-us/HT202731

Doesn't crash when external displays disconnected....

I think it has something to do with the second monitor after all.

I connected a 4K monitor to my iMac 27 on Catalina. I haven't had any crashes since I stopped using it. Since over 2 days.

10.15._3_ is what fixed it for me. No issues at all since installing it.

I have a hub that handles one Samsung monitor along with kb/mouse plus net connection. Second monitor is Acer on a usb c to hdmi adapter.

when I put enet on usb c to enet adapter, shut downs quit.

the latest update - .3 - solved my crashing issues finally. Half a week in and no crashes on sleep / wake with external displays. Sometimes it even remembers which monitor is which!

Why not give 10.15.4 a shot and see how it works before going back to Mojave?

Good news, upgrading to 10.15.6 seems to have fixed my problem.

try tuning off hardware acceleration in settings for both apps

FTR, still zero crashes today since excluding those locations from Spotlight's indexing.

I ran the update this morning. I don't recall how long it took, so let's call it 9am (one hour after my original post). It is 3pm now, and I have not had any panics or reboots.

I am now on 10.15.1 (19B86a). I have not had a chance to put it to work (with Chrome and all), so I will continue to play with it, and reply here again if I have any more issues.

In my end Catalina crashes (one-two times a day) fixed with 10.15.3 beta (iMac 2019 with two 4k display under thunderbolt) 3 days without crashes....

For download the 10.15.3 just enroll the developer program and that's it.

Been getting a similar issue. I seem to be able to stop the crash when I change the Screen Saver to something other than Catalina.

I have a Mac mini, 2018 and have two Apple LED Cinema Displays, connected via adapters from Thunderbolt to DisplayPort. I see that 10.15.3 has fixed it for someone, lets hope it does. I keep sending crash reports to Apple!