Reading Assembly info inside VS fails when assembly does not exist

[RobertvanderHulst]

Report from customer:

heute hatte ich einen Crash in Visual Studio. Ich habe nichts besonderes gemacht. Im Eventlog habe ich die folgende Info gefunden:
Application: devenv.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.IO.FileNotFoundException
   at System.IO.__Error.WinIOError(Int32, System.String)
   at System.IO.FileInfo.get_Length()
   at XSharpModel.XAssembly.Read()
   at XSharpModel.XProject.RefreshAssemblyReferences()
   at XSharpModel.XProject.ResolveReferences()
   at XSharpModel.ModelWalker.WalkReferences()
   at XSharpModel.ModelWalker.Walker()
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Threading.ThreadHelper.ThreadStart()