Kernel Panic on Startup

Mojave 10.14.6

I often turn off my computer when thunderstorms are in the area. Lately, booting after powering down has resulted in kernel panics. Sometimes it will successfully boot on the second attempt. Other times it keeps panicking and restarting. If that happens, I need to do a Safe Boot which works. Then I restart again and usually am successful in a normal boot.

I use Verbose booting and have tried to read the text as it scrolls by – and some text I can see as it panics is ATIcontoller.

Here are some of the contents of the crash report:

panic(cpu 8 caller 0xffffff80106dab9d): Kernel trap at 0xffffff7f93096afe, type 14=page fault, registers:
      Kernel Extensions in backtrace:[54AC3DDA-1C4B-3884-80BA-9D9E87DDC370]@0xffffff7f92f82000->0xffffff7f93028fff[FDF6F8FD-03A0-3443-BF89-A3AB1E7C80F2]@0xffffff7f93039000->0xffffff7f93478fff

This suggests there might be a problem with a video driver. This is a MacPro5,1 with a Metal-capable video card and running macOS Mojave.

I wonder if re-installing Mojave 10.14.6 (18G9323) might replace the drivers and solve the issue.


It might.

Before you try a full system install, however, you might want to download and install the 10.14.6 Combo Updater.

And, of course, make a full backup before you begin, just in case something goes terribly wrong.

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I would try something first.

Try removing the power line to reset the SMC after powering down the mac.
When starting up, hold down Command-Option-P-R to reset NVRAM. Wait for 5 startup sounds before letting go.


Okay…why five?

I ran some tests this morning. This MacPro5,1 has boot drives for Mountain Lion, Sierra, High Sierra, and Mojave.

I used the Option key to access the Startup Manager and then selected the boot volume. I was able to successfully boot into each version of macOS – including Mojave – using this method. I’m not sure what these results mean but it does provide a way to boot without having a kernel panic.

Might seem like a dumb question but… I have a big, ergonomic keyboard with very spread-out keys. The P key is on one side of the keyboard, the R key is way over on the other side, plus I need to hold down the Command and Option keys (on either side). That takes both hands.

But then I need my other hand to press the power button on the Mac (there’s none on the keyboard, it’s not an Apple keyboard). So that’s three hands total… but I only have two hands.

Can I press the power button first, and then (as quickly as possible) position my hands for all the keys I need on the keyboard? If so, how long do I have before it’s too late?

I have never timed it, but I always place left hand on some of the keys first. Hit the power button with my right, since that is the hand I have the most dexterity in and then select the rest.

Many years I used three, but learned that 5 is a deep NVRAM reset and it fixed a problem I had with booting a macmini.

Since you have several OS disks, you will have to set your boot disk after NVRAM reset.

Here is an update.

We have had a few days of nearby thunderstorms so I decided to shut down the computer during these episodes. The computer started up correctly each time it was shutdown.

I had taken the advice of @paalb and done a NVRAM reset – then waited until I had an opportunity to test. So it might have been the NVRAM reset or it might have been the multiple restarts and testing different boot drives using Startup Manager.

So far, so good. And so much easier than reinstalling macOS.