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MacOS 15.8.1 kills Firefox & Thunderbird at start

Firefox Launch failure
kuk replied 6 days ago
kuk
kuk

I need help with MacOS Sequoia 15.8.1 (24H32).

Since yesterday’s update to 15.8, Firefox and Thunderbird no longer work—regardless of the build or version. The system immediately terminates the apps with this message in the Apple error report:

System Integrity Protection: enabled Crashed Thread: 0 MainThread Dispatch queue: com.apple.main-thread Exception Type: EXC_GUARD (SIGKILL) Exception Codes: GUARD_TYPE_MACH_PORT Exception Codes: 0x0000000000000203, 0x0000000000000000 Termination Reason: Namespace GUARD, Code 2305843146652647939

Translated with DeepL.com (free version)

I need help with MacOS Sequoia 15.8.1 (24H32). Since yesterday’s update to 15.8, Firefox and Thunderbird no longer work—regardless of the build or version. The system immediately terminates the apps with this message in the Apple error report: System Integrity Protection: enabled Crashed Thread: 0 MainThread Dispatch queue: com.apple.main-thread Exception Type: EXC_GUARD (SIGKILL) Exception Codes: GUARD_TYPE_MACH_PORT Exception Codes: 0x0000000000000203, 0x0000000000000000 Termination Reason: Namespace GUARD, Code 2305843146652647939 Translated with DeepL.com (free version)
kuk
kuk Question owner
Read this answer in context

Chosen Solution

The cause was indeed the SIP integrity protections. I had to set the SIP setting to full protection and Firefox & Thunderbird starts again. I had some parts of it disabled.

Thank you for the tip above. I had my problems to filter the content for an relevant input but least...

All Replies (3)

jbr
jbr
  • Top 10 Contributor

Can you download the separate nightly.mozilla.org and try launching that one? Thanks!

jbr
jbr
  • Top 10 Contributor

If you've disabled the system SIP integrity protections, see https://bugzilla.mozilla.org/show_bug.cgi?id=2070811

kuk
kuk Question owner

Chosen Solution

The cause was indeed the SIP integrity protections. I had to set the SIP setting to full protection and Firefox & Thunderbird starts again. I had some parts of it disabled.

Thank you for the tip above. I had my problems to filter the content for an relevant input but least...

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