Roy,

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!

-Bryan Soltis
Kentico MVP

I had the same issue. I was able fix it by changing the configuration of the web service reference (right click in Visual Studio on the web reference's reverence.svcmap node and click "Configure Service Reference..."). I unchecked all the Kentico dlls from the list of referenced assemblies.