macOS Catalina ‘BAD MAGIC! iBoot panic header’ Bug

[German]Currently, Apple users suffer from a bug in macOS Catalina, which appears during a new installation. Those affected end up in a hanging boot process because macOS Catalina is not found. The log files contain the entry "BAD MAGIC! (flag set in iBoot panic header), no macOS panic log available", i.e. no macOS is found.


Tip from a blog reader

German blog reader Marco H. contacted me yesterday by mail to point out a problem in Apple's macOS. He wrote:

first of all thank you very much for the great posts! I'm relatively new to the "Apple" universe, but still have something that unfortunately hasn't been noticed by various IT news sites so far.

It's about a macOS Catalina bug, which probably affects quite a lot of Apple devices with a built-in T2 chip. (MacBooks, Mac Minis, Mac Pro, etc.) Unfortunately it is currently unclear whether this is a pure software bug or even a hardware issue.

Unfortunately, the issue has also affected some users from Germany. Maybe this is worth a small contribution, that maybe more people will be made aware of it, because since the start of the thread with about 200 answers and 7.4k views there is no answer from Apple regarding the problem.

Marco also referred me to the discussion in the Apple forum. At this point I would like to thank Marco for the hint.

Discussion of issue in the Apple Forum

The bug with the hanging macOS is reported in the Apple forum in the thread "BAD MAGIC! (flag set in iBoot panic header)" — Catalina freezing all the time! The thread starter writes the following in early November 2019:

I formatted my Mac and reinstalled macOS, the solution I was hoping to frequent freezing (after about 30 minutes of normal use). To my terrible surprise, my Mac still froze. A hard shutdown and restart and here I am.

The log says this: "BAD MAGIC! (flag set in iBoot panic header), no macOS panic log available"

I'm at a loss. I haven't installed any software and it froze. A quick hardware diagnostics didn't find anything wrong with my hardware. This is a new 2018 MacBook Pro. It was working great until Catalina.

This is terrible. I place myself in the helpful hands of the internet in the hopes of solving this.

The user was affected by a sporadic freezing of his device with macOS. The device froze 30 minutes after starting. So the idea was to format the system partition and install macOS Catalina again – we know this from the Windows world.

But that went wrong thoroughly. After formatting the Mac disks and reinstalling macOS, the user got an operating system that no longer starts. The iBoot component cannot find macOS.


BAD MAGIC! (flag set in iBoot panic header), no macOS panic log available
(Source: Apple-Forum)

If you search the Internet for the error message, not only the Apple forum thread linked above is ejected. This thread from July 2019, also from the Apple forum, complains about the bug since the upgrade to macOS 10.14.6, although the bug occurs sporadically. The screenshot above shows the error message someone posted in this Apple forum thread in early December 2019. You can also find corresponding notes on Within this post someone suspects the T2 chip as the cause:

Specs don't matter since it's the T2 chip making it run like crap … What's concerning is the bugs seem to be born out of apple's desire to remove boot sequence controls/power from intel cpu and route that to their T2 chip, making a custom boot sequence. Shouldn't this be developed behind the scenes? Right now it's being rolled out in a beta state.

How many different models of T2 are we looking at here in this forum that people are reporting all these bugs from, making the system unusable. How scary, Apple has all these varieties of T2 chip already and not a single one is bug free. Greta says how dare you Tim Cook. Landfill created by refunds due to engineering laziness.

Parts of the boot sequence seem to depend on the T2 chip, which is causing problems. As far as I have seen, there seems to be no solution in sight so far – there is no comment from Apple.

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5 Responses to macOS Catalina ‘BAD MAGIC! iBoot panic header’ Bug

  1. JohnIL says:

    Lot's of issues for sure, I have a 2019 MacBook Air no problems with Mojave but after Catalina loads of strange issues. From random boots, will not wake from sleep on battery. Have done all the resets Apple suggests and even did a clean Catalina install. I think Apple is having same problems as Microsoft trying to get new OS releases out the door that are stable.

  2. Mike H. says:

    I only hear reports, no help. I own a MacMini 2020. It was delivered with Catalina installed. Same bug shows up as soon as I want to install a security update or Big Sur. Nothing works, not even a clean install. Last call with support as of today Fr. 7th May 2021, the support had never heard of that problem and just tries to get me through the basics. This is getting ridiculous.

  3. Mason says:

    Same problem here. 2018 MacMini. Catalina currently installed. Can't update to Big Sur. Haven't tried a clean install yet because of time and not wanting to wipe the system clean.

    Hoping someone finds a solution for this!

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  5. constantine says:

    I had open a dj programm rekordbox and in 10 minutes of using it freezes and reboot my Mac….

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