I just installed SP1 for VS2010, and since then I get error messages from Resharper for stuff that used to work and be ok for Resharper (5.1) before.
The error messa
The solutions of @Andrew Finnell and @Julien Bérubé, alone and combined, did not fix my problem of "Cannot resolve symbol".
The comment of @bdwakefield pointing to here finally shed light on my problem.
It turns out that my "not resolved symbol" contains a web reference, and ReSharper gets lost there somehow.
By the link above it is possible to see that this is also an issue for many people, but JetBrains guys were not able to reproduce the error until now (see here).