Software⏱️ 2 min read📅 2026-05-31

How to Fix: Multiprocessing causes Python to crash and gives an error may have been in progress in another thread when fork() was called

Error in multiprocessing due to shared state between processes. Solution involves using Queue or Manager for inter-process communication.

Quick Answer: Use Queue or Manager from multiprocessing library to pass data between processes, avoiding shared state issues.

📋 Table of Contents

  1. 💡 Why You Are Getting This Error
  2. ✅ Best Solutions to Fix It
  3. 💡 Conclusion

Multiprocessing in Python can be a powerful tool for parallelizing tasks, but it also introduces some complexities. One common issue that developers face is the 'may have been in progress in another thread when fork() was called' error.

💡 Why You Are Getting This Error

  • [Cause]

✅ Best Solutions to Fix It

Method 1: Using Process Pooling with Fork

  1. Step 1: Import the multiprocessing library and create a ProcessPoolExecutor.

Method 2: Using Process Pooling with Spawn

  1. Step 1: Import the multiprocessing library and create a ProcessPoolExecutor.

Method 3: Using Multiprocessing Pool

  1. Step 1: Import the multiprocessing library and create a Pool.

💡 Conclusion

By following these methods, you can fix the 'may have been in progress in another thread when fork() was called' error and achieve efficient multiprocessing in Python.

Did this fix your problem?

If not, try searching for specific error codes.

🔍 Search Error Database

❓ Frequently Asked Questions

🛠️ Related Fixes

How to Fix: Pc crashes shortly after launching game (rainbow

Pc crashes shortly after launching game, possible cause: outdated grap

How to Fix: Installing an APK on a locked down phone

Installing an APK on a locked down phone: Try using a rooted device, e

How to Fix: FPS drops

FPS drops in games can be caused by high system resource usage, outdat