8/17/2012 9:09:16 AM
RE:Error when trying to build site after Upgrading
I encountered this issue just this morning. Very cryptic error with no real explanation. I had not modified this project in any way since the last time I built it, but started getting that same error. I tried Rebuilding the project, cleaning out the ASP.NET temp files, and restarting, all to no avail.
I did try the web.config change Helena recommended (which I also found online) but receive a “Failed to create AppDomain” error. After scratching my head a bit I decided to remove the web service reference I had to a 3rd party system. Once I removed (and my code that referenced the service) that the solution built fine.
I added the service reference back and my code and built successfully again. I’m not sure what caused the issue, but that seemed to resolve it. I have access to the 3rd party web service machine so I went ahead an rebooted that, as well.
Perhaps dropping your service, rebuilding, then adding it back may resolve it for you. Hope it works for you!