# Waitmutex exited with code 6 (MSB3037) **URL:** \ **Category:** C++\ **Tags:** UProperty, unreal-engine, Visual-Studio, CPP, question\ **Created:** [January 12, 2021, 12:58am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119 "2021-01-12T00:58:47Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Roboboy258](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Roboboy258](https://forums.unrealengine.com/u/Roboboy258)\ **Post date:** [January 12, 2021, 12:58am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/1 "2021-01-12T00:58:47Z")
So I was scripting, following a series when I ran into this problem. I know this error can be caused by UPROPERTY, but I have no idea what triggers this conflict. Here is my UPROPERTY code: ![326982-help.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/8/f/8/8f8cc0d2c15e323ca2b262f38e8fb37e689e4a57.png) (this is a header file) Severity Code Description Project File Line Suppression State Error MSB3073 The command “E:\UE\_4.26\Engine\Build\BatchFiles\Build.bat FPSGameEditor Win64 Development -Project=“E:\StealthGame\_ProjectBase\_4.25\StealthGame\FPSGame.uproject” -WaitMutex -FromMsBuild” exited with code 6. FPSGame E:\Visual Studio stuff\MSBuild\Microsoft\VC\v160\Microsoft.MakeFile.Targets 46 Any help will be appreciated. Thanks! ---
**Author:** ![Roboboy258](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Roboboy258](https://forums.unrealengine.com/u/Roboboy258)\ **Post date:** [January 12, 2021, 1:55am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/2 "2021-01-12T01:55:47Z")
It says I’m using 4.26 in the dir, but I’m using a downloaded template that was made in 4.25. ---
**Author:** ![Roboboy258](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Roboboy258](https://forums.unrealengine.com/u/Roboboy258)\ **Post date:** [January 12, 2021, 7:53pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/3 "2021-01-12T19:53:51Z")
Never mind. I spelt category wrong. For anyone else who has this error, check your UPROPERTY code for any misspelling. ---
**Author:** ![Ali\_Abdelsalam99](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Ali\_Abdelsalam99](https://forums.unrealengine.com/u/Ali_Abdelsalam99)\ **Post date:** [May 12, 2021, 12:34am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/4 "2021-05-12T00:34:55Z")
![338571-capture1.png](https://d3kjluh73b9h9o.cloudfront.net/original/4X/0/6/a/06a2c79291156b3ed77a877e9857a7e2df0caf36.png) what i can do to fix that i don’t understand what you mean?? ---
**Author:** ![Ali\_Abdelsalam99](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Ali\_Abdelsalam99](https://forums.unrealengine.com/u/Ali_Abdelsalam99)\ **Post date:** [May 12, 2021, 12:46am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/5 "2021-05-12T00:46:41Z")
how ??when build the project that happen what i should do to fix it?? ---
**Author:** ![cynkecn74](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@cynkecn74](https://forums.unrealengine.com/u/cynkecn74)\ **Post date:** [May 20, 2021, 10:22pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/6 "2021-05-20T22:22:44Z")
You can fix this by recheck your code at the line you declared UPROPERTY you maybe misspelling some word in that line wrong. ---
**Author:** ![Ali\_Abdelsalam99](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Ali\_Abdelsalam99](https://forums.unrealengine.com/u/Ali_Abdelsalam99)\ **Post date:** [May 21, 2021, 12:48pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/7 "2021-05-21T12:48:17Z")
You can explain more because i’m begineer in this track ---
**Author:** ![cynkecn74](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@cynkecn74](https://forums.unrealengine.com/u/cynkecn74)\ **Post date:** [May 21, 2021, 6:32pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/8 "2021-05-21T18:32:23Z")
Can I have the picture of your code please? ---
**Author:** ![Ali\_Abdelsalam99](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Ali\_Abdelsalam99](https://forums.unrealengine.com/u/Ali_Abdelsalam99)\ **Post date:** [May 22, 2021, 9:01am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/9 "2021-05-22T09:01:55Z")
When i open that project the photo is above is happen no code ---
**Author:** ![Ali\_Abdelsalam99](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Ali\_Abdelsalam99](https://forums.unrealengine.com/u/Ali_Abdelsalam99)\ **Post date:** [May 22, 2021, 11:06am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/10 "2021-05-22T11:06:18Z")
I don’t write any code ---
**Author:** ![cynkecn74](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@cynkecn74](https://forums.unrealengine.com/u/cynkecn74)\ **Post date:** [May 22, 2021, 9:13pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/11 "2021-05-22T21:13:54Z")
On the right side of your picture above you’ll see ‘Source’ maybe click on that. ---
**Author:** ![PISCOMAI](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@PISCOMAI](https://forums.unrealengine.com/u/PISCOMAI)\ **Post date:** [September 5, 2022, 6:36am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/12 "2022-09-05T06:36:29Z")
life saver!just a spelt sth wrong ---
**Author:** ![ixoh](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@ixoh](https://forums.unrealengine.com/u/ixoh)\ **Post date:** [January 11, 2023, 5:14am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/13 "2023-01-11T05:14:25Z")
I add the same problem and the problem for me was the fact I didn’t have closed unreal engine before launching the compile ( read the output log not the compile error list) ---
**Author:** ![ChakaPataPon](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/chakapatapon/32/602601_2.png) [@ChakaPataPon](https://forums.unrealengine.com/u/ChakaPataPon)\ **Post date:** [January 11, 2023, 1:19pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/14 "2023-01-11T13:19:24Z")
Hey guys! Im stuck with the same WaitMutex error… I checked spelling. Any further ideias. im stuck. ![helpC++](https://d3kjluh73b9h9o.cloudfront.net/original/4X/8/1/5/815544361798f6a0b750461d4ea03647ae146a95.jpeg) ---
**Author:** ![lovelacestudio](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@lovelacestudio](https://forums.unrealengine.com/u/lovelacestudio)\ **Post date:** [February 28, 2023, 5:01pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/15 "2023-02-28T17:01:40Z")
It worked for me by choosing rebuild instead of built ---
**Author:** ![tom.eberhard](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@tom.eberhard](https://forums.unrealengine.com/u/tom.eberhard)\ **Post date:** [April 13, 2023, 5:06am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/16 "2023-04-13T05:06:04Z")
> [@ixoh](#): > > the problem for Had the same mutex error on a brand new project, the “close Unreal and Rebuild” method worked for me. This was for a blueprint project where I added a C++ class to fix the Off World Live packaging issue. > **[How to package the Toolkit/ use with Visual Studio in Unreal Engine 5](https://knowledge.offworld.live/en/owl-toolkit-quick-guides/how-to-package-the-toolkit-with-unreal-engine-5)** > > How to package the Toolkit/ use with Visual Studio in Unreal Engine 5 Just updated from UE 5.1 to 5.1.1 ---
**Author:** ![letthemicefree](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/letthemicefree/32/989563_2.png) [@letthemicefree](https://forums.unrealengine.com/u/letthemicefree)\ **Post date:** [June 12, 2023, 8:25pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/17 "2023-06-12T20:25:51Z")
This error can trigger in multiple situations 🥵. For example, **it can be caused by a duplicate .cpp filename** or by a typo or wrongly placed UPROPERTY macro. I wonder if there is a way to make this error more informative for the user? If this error is caused by a UPROPERTY (many causes are possible), I have found that Rebuilding the project can trigger an actually informative warning message to appear, but for duplicate filenames, there is no way to get more information about the underlying error. ---
**Author:** ![utopia.Game2](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/utopia.game2/32/763789_2.png) [@utopia.Game2](https://forums.unrealengine.com/u/utopia.Game2)\ **Post date:** [July 18, 2023, 9:50am UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/18 "2023-07-18T09:50:22Z")
ye…@lovelacestudio your solvation worked for me … in visual-\> games → your project name → right click and rebuild ---
**Author:** ![promo\_von\_promo](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@promo\_von\_promo](https://forums.unrealengine.com/u/promo_von_promo)\ **Post date:** [August 25, 2023, 12:38pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/19 "2023-08-25T12:38:36Z")
This was also the answer for me. I updated Visual Studio (Community Edition) and received this error during my next build. Cleared Binaries/Intermediate folders and regenerated Visual Studio files and I still got the error. A Rebuild Solution was what worked for me. ---
**Author:** ![KeshavanthKumar](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@KeshavanthKumar](https://forums.unrealengine.com/u/KeshavanthKumar)\ **Post date:** [October 17, 2023, 5:27pm UTC](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119/20 "2023-10-17T17:27:11Z")
Close UE5 and rebuilt it [Next page](https://forums.unrealengine.com/t/waitmutex-exited-with-code-6-msb3037/477119.md?page=2)