If you've been using our docker tools you've noticed we depend highly on network sharing for Docker for Windows. For the Linux host to mount your Windows drives, you need to provide a username/password. What you may not realize is Linux has some special characters it may not always handle.
Short story: if you're having trouble with volume sharing & Docker for Windows, make sure you don't have a $ in your password. " and ; are also suspect at this point. Simply changing from these characters to alternate characters across the top of your numbered keyboard should work.
The Docker folks say they're working on solving this, but at least for 1.12.0-beta21 (build: 5971), we can confirm this is a problem.