I know that there are many threads on this but I tried all possible solutions without any success.
I have a solution with multiple projects. Project A has a reference to project B. In my A.csproj:

<ProjectReference Include="..BB.csproj">
      <Project>{795b8266-e62c-4d04-b8eb-cfrf5a31f55x}</Project>
      <Name>B</Name>
</ProjectReference>

I recently upgraded both projects Target framework from .Net Framework 4.6.1 to .Net Framework 4.8.
After the upgrade, when I build project B in VS it builds succesfully, but when I build project A I get lots of errors of type code CS0246 The type or namespace name 'B' could not be found (are you missing a using directive or an assembly reference?).
The strange thing is that when I build the solution from the VS developer command prompt using MSBuild solution.sln I get no errors, furthermore, if I change the reference from “ProjectReference” to a regular reference to the dll (browsing it), that error disappear.

<Reference Include="B, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL">
      <SpecificVersion>False</SpecificVersion>
      <HintPath>..BbinReleaseB.dll</HintPath>
</Reference>

I want to be able to build the solution straight from the UI and not from the CMD, and I don’t want to make changes to the references as I have lots more references with same errors and I’m not quite sure if that’s a good idea to change projectreference to browsed reference.

What I tried to do:

1. Made sure that there’s no .NET Target Framework mismatch, both projects A and B and others uses .NET 4.8
2. Ran Update-Package –reinstall in Nuget Package Manager CMD
3. Removed the reference and added it back
4. Cleaned solution and Build again
5. Unloaded both projects and reloaded them
6. Restarted VS in admin mode
7. Delete the project and reclone it
8. Retarget solution to different Windows SDK versions

I’m building in Release, Mixed Platforms mode