I have a Welkin project that is using Oauth and usually asks for authentication shortly after I load it up each time. Today, the project would open, and TWS would immediately crash just as my code loaded. I troubleshot this for a while; reinstalled Welkin, repaired .net, updated .net, tried everything I could think of but it kept crashing.
I loaded up another project and it worked fine.
I then learned that the sandbox org my first project was in was a sandbox that was completely down at Salesforce today (and still remains down at the time of this post).
It seems that if an environment is fully down, Welkin will crash at the point where the project usually asks for an oauth reauthentication.
I'm not sure how much longer it will be down for today, but happy to provide any details while I can before they have the org back online again!