> Without access to a lot of source code I can’t tell exactly what is going on, but...
> Until Microsoft fixes their compiler to not load their web browser it seems impossible to avoid this problem when doing lots of parallel builds.
In my past life developing applications and services on Windows, this scenario was too common — something is broken, you can't quite tell why because you don't have the source, and you can't do anything but wait for it to be fixed or find some hacky workarounds (which is tougher to do without the source).
This has been the real win on switching to an open source stack for me: you can take your tools apart, look inside them, and fix any issues. I know Microsoft has come further in this in the past few years, but it still sucks to be stuck in that kind of situation.