Question: Probably between 25 and 50% of the times I build my solution, I see this:

"[The operation you requested is taking longer than expected to complete. This dialog will close when the action completes.](https://i.imgur.com/UOtXUud.png)"

I hate this window in ways I can't describe. It never resolves, the Cancel button is never enabled, and the only way to remedy it is to kill the devenv process and load up my entire solution again, knowing full well that I've fixed nothing and I'm equally liable to see the same thing when I attempt my build.

My solution is about 60 projects in total, which are mostly C# class libraries, with a few each of web applications, web services, and console applications. However, the problem persists even when building one slice of the codebase with the majority (50) of the projects unloaded.

My problem is that the output windows doesn't tell me anything at the point at which it freezes, and I don't know how else to determine the cause of this lockup. If I were to guess, I would assume that it's a deadlock in the filesystem or something, but I don't know how to go about proving this--much less how to prevent it.

What can I do to diagnose and eliminate this from my solution so that I never see it again? In general, how can I diagnose problems that occur during a build?

Answer: 
I have seen this happen on large projects when MSBuild is running with the diagnostic switch turned on. In Visual Studio, go to Tools / Options / Projects & Solutions / Build And Run, then check the MSBuild project build output verbosity value. If its not set to Minimal, try setting to minimal and see if your builds are able to complete.
I did not try any of the above solution as by the time I tried my approach - all was well again.

My steps are as following:

1. Close VS
2. Delete the .vs folder
3. Open my solution
4. Clean Solution OK
5. Build Solution OK
6. Optional Rebuild OK