How to fix frequent WindowServer 409 bug reboots on a 2020 MacBook Pro running macOS Tahoe 26.1?

So I keep getting an error message for WindowServer, bug type 409. I have tried everything to avoid it: not using apps in full screen, only running 1 or 2 things at a time, running the built in diagnostics, rebooting in Safe Mode, etc. I'm hoping that someone on the Apple IT team will see this and fix there error in the OS code.


For reference for the community, I have a 2020 MacBook Pro 13-in running Tahoe 26.1. Generally what happens is I step away from my computer for anywhere from 5-20 min, and about 80% of the time, I come back to find that it has rebooted on its own due to an error with WindowServer. Luckily, thanks so built in autosave on the things I use most, I haven't lost any work. But this problem is becoming excessive. The frequency is increasing, and I haven't found anything online to explain this. Anybody have an idea of what this is and how I can fix it? See attached photo for first page of error report.


[Re-Titled by Moderator]

Original Title: WindowServer 409 bug

Posted on Dec 8, 2025 9:56 AM

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How to fix frequent WindowServer 409 bug reboots on a 2020 MacBook Pro running macOS Tahoe 26.1?

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