I have a .NET 4.7 Solution with several projects, one of them a ServiceBase. I build the Solution, then start the service. Now it seems like the service locks every single DLL in the output folder, even the ones unrelated to the ServiceBase project. So e.g. I have a standalone Project in the solution with no references to other projects, nor is it referenced by others. Still, I can't build the project when the service is running.
Here's a helpful explanation of .NET using MMF at runtime. But it doesn't answer why I can't build an unrelated project of the same solution.