Error loading PostSharp symbol file

The solution was found here:

http://drc.ideablade.com/xwiki/bin/view/Documentation/code-first-troubleshooting#HErrorloadingPostSharpsymbolfile

I am repeating on my blog simply for redundancy purposes because the above article was the only source I found to the problem.

If you get the following Build error:

Error loading PostSharp symbol file: Access to the path 'C:\..\SomeFile.pssym' is denied.

Likely cause: you deleted solution binaries in order to clear out lingering out-of-date assemblies. Unfortunately, the PostSharp process becomes confused and prevents you from building the model assembly.

Workaround: Close and re-open the solution.