Is it possible to get a full path with double backslash by using Path.GetFullPath? Something like this:
Path.GetFullPath
C:\\\\Users\\\\Mammamia\\\\Videos\\\\Doc
C:\\Users\\Mammamia\\Videos\\Documents\\CFD\\geo_msh\\cubeOp.txt is not a valid path, so I'm not sure why you'd want it, but:
C:\\Users\\Mammamia\\Videos\\Documents\\CFD\\geo_msh\\cubeOp.txt
Path.GetFullPath(yourPath).Replace("\\", "\\\\");