Unreal Engine 5.8.1 problem with Visual Studio 2026 (18.8.2)

[Just-Manu]

I started a new C++ project with the Third Person template, installed visual studio 2026 with every requirement specified by the official Unreal Engine documentation, selected Visual Studio 2026 inside the UE editor as Source Code editor, and when I try to open any C++ class I get the same 7 errors in the Visual Studio console no matter what I do.

I’ve tried everything, Visual Studio 2022 has the same problem, Unreal Engine 5.7 has the same exact problem, I don’t know what else to do, I’ve tried every possible “fix” I could find on the internet but still nothing.

Can Anyone help me with this? I’m new with Unreal Engine and I didn’t modify anything in any file so I don’t know why I’m getting these errors.

Info: I’m using Visual Studio 2026 (18.8.2) and these are the 7 errors I’m getting no matter what I do (in the images).

The errors I’m getting are in Unreal Engine’s source code, in two files called:

• StaticAssertCompleteType.h
• IsContiguousContainer.h

Located respectively in:

• C:\Program Files\Epic Games\UE_5.8\Engine\Source\Runtime\Core\Public\Traits
• C:\Program Files\Epic Games\UE_5.8\Engine\Source\Runtime\Core\Public\Misc

[E_Hamza_MB]

Your project may use newer version of cpp. So can you try to change your project settings to force your project to use older cpp version. On your project build settings.

public class Wizards_RPG : ModuleRules

{

   public Wizards_RPG(ReadOnlyTargetRules Target) : base(Target)

   {

      PCHUsage = PCHUsageMode.UseExplicitOrSharedPCHs;
      CppStandard = CppStandardVersion.Cpp20;

   }

}

I’m not sure if it’s going to work or not. Please inform me.

[Just-Manu]

Thank you for your reply, I’m really frustrated with this situation…

I tried to find how to change the cpp version in the project settings, but I didn’t find an option for that…

And where should I add that code you sent?

The errors I’m getting are in Unreal Engine’s source code, in two files called:

• StaticAssertCompleteType.h
• IsContiguousContainer.h

Located respectively in:

• C:\Program Files\Epic Games\UE_5.8\Engine\Source\Runtime\Core\Public\Traits
• C:\Program Files\Epic Games\UE_5.8\Engine\Source\Runtime\Core\Public\Misc