I’m a heavy user of Parallels on my MBP since I still do all sorts of Windowy things.  Recently I was doing a .NET source code review where the source was living on an encrypted partition on my mac that I had shared to my Parallels via their shared folders feature. As it was an old project, it had to be converted and although some of the projects converted fine, I received the following error with others:

Error converting project file. Invalid URI: The hostname could not be parsed.

It would specify this as a problem with the .csproj file so I assumed it was some parameter in there.  A little while later, I was trying to do something else with a command line tool and received a similar error.  Interesting, I thought, and then it hit me as the path to the file was staring at me from the command line.  I was using the UNC path for the file and Parallels uses

1

.psf

for it’s hostname…which is not a valid hostname.  So obviously, Windows/Visual Studio was having trouble parsing this hostname!

Mapping the share to a drive letter and then opening the file from that drive solved the problem!