When I recently upgraded to Visual Studio 2015, everything seemed to go very smoothly except that whenever I debugged my main application I got a dialog window with the following strange error:

The procedure entry point could not be located in the dynamic link library C:\...\bin\Debug\netutils.dll.

After pressing OK everything seemed to work as normal.

After a considerable number of dead ends, I finally worked out that changing the name of the NetUtils.dll assembly fixes the problem. It seems that Visual Studio 2015 gets confused with a Windows system assembly with the same name. I don’t know why it was never a problem with Visual Studio 2013, but I renamed the assembly and now everything is working fine.