Error 0xc0000409, "The system detected an overrun of a stack-based buffer"

This code is Windows stopping a program that wrote past the end of a buffer on the stack, which could let an attacker take control of it. Microsoft's name for it is STATUS_STACK_BUFFER_OVERRUN. It is usually a bug in the program, but bad drivers, faulty RAM, and software that injects itself into other programs can cause it too.

The fix, in order

  1. Update the program that crashes. A stack buffer overrun is usually a bug the maker already fixed, so install the latest version from the official source and check the maker's release notes for a crash fix.
  2. Reinstall the program cleanly. Uninstall it, restart, and install a fresh download. A damaged install can corrupt the data the program works with and trigger the same overrun.
  3. Close overlays and injecting software. Game overlays, recording tools, and some security software inject code into other programs, and a bad injection is a common trigger. Close them one at a time and test after each one.
  4. Run a full malware scan. Use Windows Security or your installed security software to run a full scan, since malware that tampers with running programs can cause exactly this crash.
  5. Test the RAM. Search for Windows Memory Diagnostic, run it, and restart when asked. Faulty RAM corrupts data as programs use it, and that corruption can look like a buffer overrun.
  6. Update graphics and chipset drivers from the PC or hardware maker's support page, and install any pending Windows updates, since driver bugs are another common trigger.
  7. Repair Windows files. In an admin Command Prompt run sfc /scannow, then DISM /Online /Cleanup-Image /RestoreHealth.
Do not disable Data Execution Prevention or other exploit protections to work around this. Those protections are what caught the overrun, and turning them off lets the buggy program keep running with a live security hole instead of crashing safely.

If it still happens

If the crash happens at the same moment every time, such as opening a specific file or level, the trigger is in that data, so try a different file, verify the game files, or ask the maker whether that content is a known crash. If it happens across many different programs, test the RAM and scan for malware first, since a program-specific bug cannot explain crashes everywhere at once.

Common questions

Is 0xc0000409 a virus? The code itself is not a virus, it is Windows stopping a program that wrote past the end of a buffer. That kind of bug is exactly what malware tries to exploit, so a scan is sensible, but the usual cause is a bug in the program, a bad driver, or faulty RAM.

Can I fix 0xc0000409 myself? Yes, in most cases, by updating or reinstalling the program, removing software that injects itself into other programs, and testing the RAM. If the bug is inside the program itself, only the maker can fix it, and your part is to update to the version that contains the fix.

Why does 0xc0000409 happen in many different programs? When it hits many programs, the cause is usually shared: faulty RAM corrupting data, a bad driver, or malware. A single program crashing this way points at that program, while many programs crashing this way points at the hardware or the system underneath them.

Related errors

Error 0xc000001d · Error 0xc0000005 · Error 0xc0000006

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