My guess would be that it's an automated build / deploy system that required some addon installed to run, so they had to run `devenv /build` instead of using msbuild. Then they saw this behavior on one of their build machines when something wasn't installed correctly and the process just terminated, after 71 retries...
Source: I was on the visual studio environment team a decade ago, and Rube Goldberg himself could not design a build process that would surprise me, at this point.
That makes sense... I was imagining that there was some build process that froze VS 99% of the time and some poor developer was sitting at his desk silently crying into his coffee trying over and over to get his project to build so that he can go home for the weekend.
One main project (open all day) and small projects throughout the week/month with a machine never shut down? I can see that happening easily at web agencies and the like.
Step 2 in the reproduction case also includes shutting down the new instance, so I think there is only ever a maximum of two instances at a one time. Seems that the unusual bit is that 70 instances are opened without ever closing the very first instance.
It's not multiple instances running at the same time, step 2 kills an instance. It's one "main" instance running continuously, then opening and closing a second instance over and over.
Maybe it happens if you click on a cs or sln file and then press shift and click somewhere else. This might select all sln or cs files and invoke open on all of them, launching many instances at once. Happened to me once with another programm
