C:\Users\richardd\AppData\Local\Temp\Temporary ASP.NET Files\siteName
Clear out the project MRU list
Apparently Visual Studio sometimes accesses the files in your your recent projects list at random times, e.g. when saving a file. I have no idea why it does this, but it can have a big performance hit, especially if some are on a network share that is no longer available.
To clear your recent project list out, delete any entries from the following path in the registry: