Error Mutant Limit Exceeded 587 (0x24B): How to Fix it

Adjusting your code can help you handle mutex properly

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ERROR_MUTANT_LIMIT_EXCEEDED

ERROR_MUTANT_LIMIT_EXCEEDED is a Windows error that usually affects developers, but if you ever encounter it on your PC, the steps from this guide will help you fix it.

How can I fix ERROR_MUTANT_LIMIT_EXCEEDED?

1. Ensure mutex is handled properly in your code

  1. Open your code.
  2. Handle mutex like this:
    HANDLE hMutex = CreateMutex(NULL, FALSE, NULL);
    if (hMutex) {
        WaitForSingleObject(hMutex, INFINITE);  // Lock
        // Critical section
        ReleaseMutex(hMutex);                  // Unlock
        CloseHandle(hMutex);                   // Clean up
    }

    handle mutex
  3. Save changes.
  4. If recursion is necessary, don’t exceed the limit of 1000 locks per single thread.

Keep in mind that every WaitForSingleObject or WaitForMultipleObjects needs to have ReleaseMutex to avoid problems.

2. Other tips to use

  1. Ensure that no thread is stuck waiting for a mutex that is never released.
  2. Use the WaitForSingleObject function to avoid indefinite waiting.
  3. You can also use NtQueryMutant to monitor the state of mutex and adjust the application accordingly to avoid issues.
  4. Use tools such as Process Explorer or Resource Monitor to identify processes with high handle counts or threats holding mutexes.
  5. Use DebugDiag or Windbg and attach them to the application to monitor the mutex usage.
  6. Add counters for Handle Count or Thread Count in Performance Monitor for specific processes.

Sometimes you won’t get ERROR_MUTANT_LIMIT_EXCEEDED, and instead, you might see the following message: 587 (0x24B) An attempt was made to acquire a mutant such that its maximum count would have been exceeded.

As you can see, this is a programming error, and in most cases, you need to properly handle mutex or use other tools to identify processes with high mutex usage.

This isn’t the only error you can encounter, and in the past, we wrote about SYSTEM EXIT OWNED MUTEX and THREAD_TERMINATE_HELD_MUTEX, so you might want to check them out.

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