What is causing NotSupportedException ("The given path's format is not supported") while using a valid path?
Solution 1:
According to the reference source: http://referencesource.microsoft.com/#mscorlib/system/io/filestream.cs#732
NotSupportedException will be thrown if the index of the : in your path is at the third position or later. (One would expect : to be the second character) Are you sure there are no zero-width combining characters or other similar Unicode shenanigans going on in your source?