"iMac Pro" kernel crash

I've posted this solution a few month ago - what should I say 2 panics since the modifications. I can highly recommend to give this solution a chance to stop headache. 🙂

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First, I’ve checked how often and when the system rebooted: (terminal)

last reboot

Second, I’ve checked the reboot reason: (terminal)

log show --predicate 'eventMessage contains "Previous shutdown cause"' --last 72h

code 5 is ok, I see mostly -20 but I nowhere found a correct description for this code but for sure it’s an abnormal termination.

Third, I’ve changed energy settings to (within system preferences)

• disable automatic …. when display is turned off 1
• hard disk to sleep 0
• wake for network 0 (Attention – result is that the system can’t be controlled anymore via ARD when in sleep mode etc.)
• start up after power failure 0
• power nap 0 (a few otherones wrote this as well)

Fourth, I’ve changed the hibernate mode to 0 (terminal)

(check actual status)

pmset -g

(change to mode 0, Attention: uses a bit more power)

sudo pmset -a hibernatemode 0

I ran capture data program, and they identified 3 problem applications. CrashPlan, Aladdin (a kext that has something to do with software license protection), and Backblaze. All indicated crashes. Their solution was to ask me to remove them. My external disks are using Apple TB2 converters to connect to two RAID systems that I backup to the cloud using CrashPlan and Backblaze. Not happy with their response to just remove these apps. I started one at a time to see if I could lock it down to something specific. I removed CrashPlan first, and never had another crash.

A few weeks have passed since I did this. Luckily I’ve had no issues with Backblaze. However, I decided to start playing World of Warcraft, this heavily usues IO and the disks, and apparently this was too much and started causing the crashes again. I’ve not reported the new crashes to Apple. But it defiantly seems to be IO related for almost anyone who is having the issues.

i had the same problem. My iMac Pro got replaced. And I still had the crashes. Its not Thunderbolt or T2 Security settings, its power nap function. just turn it of as mentioned. helped me.

having the same problem; apple engineering said it is faulty Radeon Pro Vega 64 video card. They are sending a tech to my house to replace my motherboard. Anyone else gotten this answer??

Does it still crash if you just use Wifi and don't use the Ethernet port at all/turn off the Ethernet port in System Preferences -> Network? Obviously that doesn't really help you use the machine the way you need to, but it would be interesting to see if it still gives you panics.

I've tried disabling all Secure Boot functions and disabling Power Nap, and I still get panics. You've tried disconnecting all your Thunderbolt 3 to Thunderbolt 2 adaptors, and you still get panics. The thing you and I are both still using though is the Ethernet port, and from your initial post that seems to be a likely culprit.

I had my Ethernet port manually set to "full-duplex, flow-control" as per another thread (Imac Pro - Crash when copy over 200GB on SMB !?), but I'm going to try turning it off in System Preference -> Network to see if that makes any difference.

Me too, 8 core/64GB/2TB SSD/VEGA 64.

Kernel Panic in low power mode even in Safe Mode. I've gone through all the steps with Apple several times so Apple sent me two replacements (to be fair I requested the first one separately as UPS delivered it frozen), same issue, eventually the Mac restarts with a kernel panic while in low power mode.

At this point unlikely that it's a hardware issue related to your or my specific unit but either an OS/Kernel glitch or an architectural issue related to the new iMacs.

So my choices are either wait and hope for Apple to release a software fix or return it, doing another exchange seems futile.

Looking at the Kernel Panic dumps looks like someone MAY have been working on it, the Kernel Version got bumped from 17.3.0 in January to 17.4.0 yesterday and it "feels" like I'm seeing fewer panics. Where it used to panic once or twice a day it now appears to panic once or twice per week.

Currently I'm leaning to wait for Apple to fix this.

Also, shout out to the AppleCare and Apple Store Genius people who have been great in trying to get this resolved and from experience no other company has treated their customers as well as Apple has treated me with this issue.

Agreed on all except my 10-core hasn’t panic’d in over a month after turning off every option in power management . Probably burning a lot of electricity but better than reboots until it gets fixed. And YAY for the garbled graphics fix in that last release!

If you look through the forum, you will see this same issue over and over again. Something apparently went a rye at the factory when they were installing the operating system. If you do an erase and then reinstall MacOS. It seems to clear most of the problems. But funny enough not all. Some software seems to still give it a hiccup. Make sure you do a complete back up to time machine on an external drive before you under take doing this or you will lose everything. If you search reinstall Mac OS on this website, Apple provides a nice tutorial on how to do it. Good Luck

This is a known issue -- with no resolution or recognition that I can find. I, literally, created another post, moments before seeing your message. It appears to be related to the Apple T2 processor, which would only affect the new iMac Pro devices.

Reinstalling the OS via the repair partition, bootable-media, or web-repair methods DO NOT solve this problem. It appears to be a root/core MacOS/iMac Pro issue.

It's worth noting that through my testing, the computer does not expose this behavior when using Bootcamp and Windows 10. Though, if it is related to the encryption co-processor, this would make sense since it's not a feature/function that is exposed to Windows.

I have created another ticket for this issue, and I will ensure that I keep this thread posted.

I have the base model with a Vega 56 - bought new at the Apple Store, had a few kernel crash since I have the machine, but not for a few weeks at least. I commented above in this thread...

It does seem to be gpu related, the only issues I had with the machine were all related to multi-display support, I ended up using only one external display, because two would cause frequent issues when coming back from sleep - that is the iMac's built in screen not coming back on until reboot & kernel crashes...

Same problem with the Vega 56. Crashes randomly being in use or not, but more often during sleep periods, especially long sleep periods, like overnight.

It’s not only related to Compressor or FCP. I’m a developer and I don’t use it at all. I got the crashes using Xcode.

Interesting thing to note is that it doesn’t crash when running in Windows. It can stay in sleep mode for days and will be just fine.

Which tells us that:

- it’s not related to the Vega card

- it’s probably not a hardware issue because the problem only happens in macOS

I got my iMac Pro back in April, it was running 10.13.4 when I got it and I updated to 10.13.5 beta, then final and the problem has remained all along. The issue does still happen in Mojave beta 2 (haven’t tried beta 3).

What puzzles me is that people on this forum almost all got the issue, yet Apple doesn’t say a word about it. I don’t have enough contacts with other iMac owners to know their experience but I’d be interested to know how common this issue is. It seems people who got their machines exchanged still face the issue with the replaced units.

The only workaround I have found is to disable the sleep feature and the Secure Boot. I rarely have crashes this way but it’s not ideal and it bugs me that such an expensive machine can’t be put in sleep mode using its native OS.

I spent a fortune on an iMac Pro 10 core machine and I have to say that it is the first Mac computer that I have been unimpressed with. All of the problems people are talking about are similar to what I have experienced from day one. I’ve called Apple care numerous times, always met with “Oh, this is the first time I’ve heard about such a thing”. I can say that I finally in complete exasperation brought that machine into the Genius Bar over a long weekend and said “Fix it”. Apparently I was told it was a software issue and the operating system was reinstalled. My machine has functioned much better since then. I also do not use Skype anymore because when I would exit from Skype it would crash the whole computer and the computer would just restart.

I’ve never spent so much on a computer to be so unimpressed. Apple KNOWS they have a problem with this machine and are keeping really silent about this.

I've gone three days in a row without a crash since I unplugged my TB3->TB2 adapter from my 2018 MacBook Pro. I used to let it sleep with the adapter attached (but nothing attached to it was powered on) and it crashed with the Bridge OS error 5 nights out of the first 7 of ownership during sleep.

I've read that others have experienced crashes with nothing but the power adapter attached, but I haven't seen this on mine yet. However, I'm only on day three of unplugging everything before sleeping the computer so that may change.

Try disabling Filevault. Fixed a similar issue I had. Apple support recommended this...

Apple Support told me to turn off the Secure Boot feature, and so far, that seems to have worked. This page About Secure Boot - Apple Support tells you how to do this. You need to check No Security.