So as of Quickbooks 2016, it appears they have disabled the ability to host a file on a remote drive within the same network.

Originally they provided documentation on how to use network available files:

Here is their update in regards to how to solve a missing file error:
*adding shortly*


To fix you simply need to make a symbolic link from your local drive to the mapped network location then reopen the file via the symbolic link full path. Note: if you attempt to click the link it will change the full path once you begin to select the file.

Hope this helps!