On Windows 11 (builds after 2022), clumsy 0.4 v2 may show "WinDivert failed to load." This is due to kernel driver signing changes. For Windows 11, consider using a more recent fork like clumsy-beta-0.4 or disable memory integrity (Core Isolation) temporarily.

However, for simplicity and speed on Windows 10, nothing beats the original release.

Then the program crashed.

While Clumsy has been around for years, the is widely considered the most stable modern release.

Leo opened a live stream of a high-stakes stock ticker. He took a breath and slid the bar to its maximum setting. He hit the button.

is a powerful, open-source utility designed to intentionally degrade network performance on Windows Vista, 7, 8, 10, and 11. It allows developers, software testers, and network enthusiasts to inject latency, drop packets, and simulate poor connections in a managed environment.

is the long-standing stable release, the project saw significant development activity in October 2023

When Mara reopened it, the gray room was empty. But the logs had changed. A single line at the bottom, timestamped just now:

If you are still running older versions, we highly recommend updating to the 2021-compatible v2 release to avoid driver conflicts on modern Windows operating systems.

Temporarily blocks traffic for a given period, then sends all accumulated packets simultaneously in a massive batch.

Check the boxes for the effects you want (e.g., Lag or Drop) and set the desired parameters.