Wednesday, November 26, 2008

ReSharper Fails to Load with a Generic Error

After installing Resharper 4.1 on Windows 2003 server, I got this message when I start Visual Studio 2008:

The Add-in 'JetBrains ReSharper 4.1' failed to load or caused an exception.

Error Message: The system cannot find the file specified.

Error Number: 80070002

I emailed JetBrains support and got a quick response.  It turns out my system did not have Extensibility.dll installed in the GAC (Global Assembly Cache), and ReSharper requires this dll to run. 

To figure this out, I opened explorer to the path "%windir%\assembly", which brings up a shell extension that displays the contents of your GAC.

The fix was easy, I just had to find the dll, which is installed with Visual Studio.  Once I knew the location, I opened the Visual Studio command prompt and ran

gacutil /i  "C:\Program Files\Common Files\Microsoft Shared\MSENV\PublicAssemblies"

Hopefully this saves someone else some time.