Dev 6071 is one of the less common problems faced by Call of Duty: Modern Warfare and Warzone players. However, it is also one of the most persistent. Code 6071 seems to ignore almost all common solutions and won’t even let you enter the game to adjust other settings. However, there is a method you can use to fix dev error 6071 that is pretty much guaranteed to work. Here’s what you need to know.
Modern Warfare and Warzone | Fix development error 6071
Development error 6071 in Call of Duty: Modern Warfare and Warzone prevents the software from starting correctly. You will hear startup sounds, but the game will display a black screen before crashing. Fortunately, you can fix dev error 6071 by diving into the Windows 10 registry and changing your machine’s UUID.
Before attempting registry fix, some of the more common troubleshooting steps are worth trying. Make sure Windows is up to date and double check that you are running the latest GPU drivers. Using the Scan and Repair tool in the Battle.net launcher is another good idea that should rule out any problematic data. Finally, we recommend that you disable all programs with in-game overlays – these seem to cause a lot of problems with the Call of Duty software. With any luck, one of these will fix the problem.
However, if you’ve come here looking for a different solution, chances are those solutions didn’t work. Apparently, there is a widely spread fix for development error 6071 that involves changing the UUID of the PC in the Windows Registry Editor. Here’s what you need to do.
How to fix dev 6071
- Go to the UUID generator website, generate a new UUID and copy it to the clipboard (CTRL + C)
- Click the Start button and open the Registry Editor
- You can also press Windows key + R, then type regedit
- When the User Account Control dialog box appears, click Yes
- In the left pane, go to HKEY_LOCAL_MACHINE> SOFTWARE> MICROSOFT> CRYPTOGAPHY
- Double click on the entry named MachineGuid
- Enter the code you copied from the UUID Generator website
- Click OK, then close Registry Editor
It’s not immediately clear why this fix works. The MachineGUID registry entry is a unique identification key for your PC. These are known as universal unique identifiers (UUIDs) or, alternatively, globally unique identifiers (GUIDs). Changing that somehow tricks the Call of Duty software into thinking it’s on a different computer – one capable of running the game, it seems.
That said, there is some precedent for this fix. After the release of Modern Warfare 2019, users experiencing development error 6071 reported that only a fresh install of Windows would fix the problem. This is a terrible solution for many reasons, not the least of which is wasted time. However, reinstalling Windows only happens to generate another UUID, which in turn solves the problem. Strange, right?
Do not use the same UUID code!
There are several versions of this fix where users recommend using a specific UUID, for example in this YouTube video or this Activision support forum thread . However, using the same UUID string is not recommended for security reasons. It might work, and if all else fails, you can try it, but we don’t consider fixes with security issues to be adequate solutions.
The risks outweigh the benefits – a common UUID can be used to find your MAC address or discover other personal information. This is why it is critical to generate a unique code when using this fix.
After changing the MachineGuid registry key to a unique identifier, try starting Modern Warfare or Warzone again. You should find that the dev error 6071 has been miraculously fixed. This is a very strange solution to a rather rare problem, but apparently it works for the vast majority of users. If not, you will unfortunately need to get in touch with Activision support.