Downloaded and tried upgrade a site residing on D:. This seems to be impossible with R2 installer! Is it by design or a bug? Install package in program files on C:
EPiServerInstall Warning: 0 : System.InvalidOperationException: The installation failed, and the rollback has been performed. ---> System.IO.IOException: Source and destination path must have identical roots. Move will not work across volumes.
at System.IO.Directory.Move(String sourceDirName, String destDirName)
at EPiServer.Install.FileSystem.Installers.RemoveDirectoryInstaller.Install(IDictionary stateSaver)
at System.Configuration.Install.Installer.Install(IDictionary stateSaver)
at System.Configuration.Install.TransactedInstaller.Install(IDictionary savedState)
--- End of inner exception stack trace ---
Have a look at this thread: http://world.episerver.com/Forum/Pages/Thread.aspx?id=24578&epslanguage=en