ReSharper 5.1 can't navigate to a type from anywhere

I'm running Visual Studio 2010 (10.0.40219.1 SP1Rel) with ReSharper 5.1 (5.1.3000.12). Recently, it seems as though ReSharper has completely lost the ability to navigate to a type.

Here are some actions I can take in the UI that now do nothing:

1. Right-click on type name in code editor and select "Go To Declaration"

2. Right-click on type name in code editor and select "Go To Implementation"

3. R# "Go to type" (Ctrl-T)

4. In the R# "Find Results" window, double-clicking a type

Here are some actions that still work:

1. Double-clicking an item in Solution Explorer
2. Opening a file from VS Command Window

I've completely uninstalled Visual Studio, then reinstalled it with SP1, and ReSharper 5.1, and I still have the same problem.

I'm assuming there's some kind of configuration open that I've done that is disabling the ability to navigate to a type with ReSharper, I just can't figure out what it is.

Any advice would be much appreciated.

I am using VS 2010 SP1 (same as you)

Delete the Resharper temp files in the same location as your solution file. The folder name will be something like _ReSharper.SomeSolution

Failing that, try one of the R# nightly builds here altho it should work with your current config.