Why won't this Path.Combine work?

I have the following command:

string reportedContentFolderPath =
Path.Combine(contentFolder.FullName.ToString(), @"\ReportedContent\");

When I look in the debugger I can see the following:

contentFolder.FullName = "E:\\"

However

reportedContentFolderPath = "\\ReportedContent\\"

Why is the Path.Combine chopping off the E:\?