After following steps in this link, I found that my projects would still not build correctly. The error I got in the build was: "The path C:\Documents and Settings\myBuildServiceUser... Settings\Temp\myProject\Bui... is already mapped in workspace myBuildServerMachineName_16." To fix this problem you need to delete all workspaces on the build server (owned by the user account that the build service runs as) - these are named buildservername_nn where buildservername...