If you are working with WinRT to develop store apps (for Win8 or Win8.1) currently you most probably have been using the new Storage APIs.
This function accepts a full path and returns a StorageFile that you can use to work with that file. If you look at the MSDN article on this you will note that there is a comment in the parameter section that says
"If your path uses slashes, make sure you use backslashes (\). Forward slashes (/) are not accepted by this method."
If you do have the wrong slashes you would get a "Path is invalid" exception. This fine if you are generating the path and you can put in the right slashes in when building the path.
But today, I came up against a scenario I did not expect. Since I don't like working with string paths, I usually work with System.Uri. In this case I was passing around an Uri and passed uriVariable.AbsolutePath and was surprised when I got the Path Invalid exception. Looks like the Uri object stores paths with Forward slashes ("/"), which the GetFileFromPathAsync does not like. Well two part of the framework that work with two different representation of paths..
Well the solution is simple, but I did spend a good 30 minutes trying to sort this one out as I initially thought the path was really wrong and this error is not very well documented elsewhere and so google searches did not turn up much.