Starting Dynamo

Hi, I´m trying to start Dynamo, but when I opened It fails.
Please Help!

It says:
Method failed with unexpected error code 50.

at Dynamo.Graph.Workspaces.WorkspaceModel.SaveAs(String newPath, RuntimeCore runtimeCore, Boolean isBackup)
at Dynamo.Models.DynamoModel.b__3b()
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler) seems related - do you have write access to this location?

Try to reinstall dynamo again.