I have an existing Visual Studio 2005 project that compiles and runs fine. I
opened the project in Visual Studio 2008 and let it upgrade the project to
the new framework and verified that it still compiles and runs fine. I then
went into project properties and changed it to target .NET Framework 3.5.
After Visual Studio 2008 closed and reopened the project, ReSharper 4.0
showed false errors on nearly every line of the project.
To clear the errors, I had to close Visual Studio 2008, removed all the
_ReSharper* cache folders from my temp folder, and then reopen the project.