UNC paths that point to individual files should work.

What happens when you try to access one? And could you get us a net-internals log from a failed attempt? Instructions for getting one can be found here: https://sites.google.com/a/chromium.org/dev/for-testers/providing-network-details

Network bug triager here.  Friendly ping, can you respond to comment #1?

Please reopen with the requested information if this is still happening.