I have a project that I have worked on for several years. It references a dll that is in a different project. Today, I got an odd error message, and when attempting to debug it, decided that part of the problem was that I was targeting the release version of that dll, which prevented me from seeing something that seemed likely to matter.

That's a simple problem, so I switched to the debug build of the dll. That resulted in a few other errors about an interface having the wrong signature for a method. That was a change I made years back. It was as if the project had reverted partly to some older version that was no longer in use...or even in existence.

That was really weird. Rebuilding did nothing, cleaning did nothing, so I went and deleted the bin and obj files and rebuilt...it simply won't. I've tried it a couple times. Either the bin and obj folders are not created, or they are created but only either release or debug folders are created under there (I'm only building the debug version, so why is only the release folder being created...but only sometimes), and the folders are empty when they are there.

So, it's giving no errors, the icon imagery suggests that it really is building the thing, but it isn't creating any output, including not always producing the folders that it should...though sometimes it creates them and sometimes they are empty.

Any suggestions?