Can't build UE4 sln after regenerating it from uproject file

I was having issues with code, so I decided to regenerate my projects SLN file, and then rebuild the whole project.

It was a really bad idea, I can’t even open my project again.

Anytime I try to start the project, it says, the project was build with a different version of the engine… although it wasn’t.
When I choose yes for rebuilding now I end up with a message on screen saying, that it can’t be built, and I should rebuild manually…

I had a look around and found this:

  • I deleted my Intermediate and Config folders
  • I right clicked my uproject file, and chose generate VS solution.
  • I double clicked that, and chose build and rebuild for all
    the solutions in there and

I get this error message after the build finished:

Severity Code Description Project File Line Suppression State
Error (active) E0493 no instance of overloaded function "std::pair<_Ty1, _Ty2>::pair" matches the specified type GITVR C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.26.28801\include	uple 991
Error (active) E0145 member "FBulkDataStreamingToken::InvalidOffset" may not be initialized GITVR E:\Jani melok\Unreal\UE_4.25\Engine\Source\Runtime\CoreUObject\Public\Serialization\BulkData.h 196
Error (active) E0145 member "FBulkDataBase::InvalidToken" may not be initialized GITVR E:\Jani melok\Unreal\UE_4.25\Engine\Source\Runtime\CoreUObject\Public\Serialization\BulkData2.h 109
Error (active) E1574 static assertion failed with "TAtomic is only usable with trivial types" GITVR E:\Jani melok\Unreal\UE_4.25\Engine\Source\Runtime\Core\Public\Templates\Atomic.h 537
Error (active) E0145 member "FName::StringBufferSize" may not be initialized GITVR E:\Jani melok\Unreal\UE_4.25\Engine\Source\Runtime\Core\Public\UObject\NameTypes.h 466
Error (active) E0145 member "FNavigationLinkBase::InvalidUserId" may not be initialized GITVR E:\Jani melok\Unreal\UE_4.25\Engine\Source\Runtime\Engine\Classes\AI\Navigation\NavLinkDefinition.h 40
Error (active) E0145 member "Chaos::FImplicitObject::D" may not be initialized GITVR E:\Jani melok\Unreal\UE_4.25\Engine\Source\Runtime\Experimental\Chaos\Public\Chaos\ImplicitObject.h 121
Error (active) E0145 member "FShaderParameterBindings::kInvalidBufferIndex" may not be initialized GITVR E:\Jani melok\Unreal\UE_4.25\Engine\Source\Runtime\RenderCore\Public\Shader.h 574
Error C4102 'https': unreferenced label GITVR E:\Jani melok\Unreal\UEProjects\MyProjectname\Plugins\VictoryPlugin25\Source\VictoryBPLibrary\Private\VictoryBPFunctionLibrary.cpp 1736
Error MSB3073 The command ""E:\Jani melok\Unreal\UE_4.25\Engine\Build\BatchFiles\Build.bat" GITVREditor Win64 Development -Project="E:\Jani melok\Unreal\UEProjects\MyProjectname\GITVR.uproject" -WaitMutex -FromMsBuild" exited with code 6. GITVR C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\VC\VCTargets\Microsoft.MakeFile.Targets

EDIT: tried the steps advised by Ben from here, but still getting errors…

“…and Config folders” - ummm…don’t think this ever needs to be done. I would restore this back.

I have only ever deleted binaries and intermediate when wanting to do a clean build.

When you right click you .uproject, select “Switch Unreal Engine version…” it will show what version/engine build it was last set to.

I see that you have a space in your folder’s name (E:\Jani melok) I’m not sure if this could cause compile issues but who knows.

You deleted the wrong folders. If you want to “Clean” your solution you delete the Binaries, Intermediatte and sometimes the ‘Saved’ folder. You should never delete the “Config” folder - it contains all of your project-wide settings. It’s not the end of the world as they can be regenerated - but you will need to setup all of those project settings again.

Try doing it again from scratch, this time deleting the right folders. Also delete the hidden .vs folder and the solution file. Make sure the .uproject file is using the correct engine version too.

Did you change or upgrade the version of Visual Studio and are you working from a source build of the engine or the launcher version?

Sorry for late replies, I am AFK at the moment. I just copied the Contents folder over to a similar version of the project, and it’s ok for now…

But I had a similar issue after cloning the same repo, on a workstation next to mine…
​​​​​​Have to find out why…

Once I am back to work I have a look and update my post.

Clone only Content, Config, and .uproject. Use the uproject to generate the solution and build the binaries.

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In case somebody else sees this - the E0145 ‘errors’ are actually just intellisense complaining and can be ignored. In the errors list in VS 2017 there is a dropdown where you can select ‘Build Only’ instead of ‘Build + Intellisense’ that will filter out those errors. Once those are gone you will see only the errors that are actually preventing you from successfully compiling.