Running a Windows 2012 R2 DFS with Deduplication enabled on the storage drives. Both Macs and PCs regularly interact with the system with no issues.
However with Apple's rollout of 10.9.2 SMB2 'fix' users are no longer able to correctly interact with any files on the file server with the "SparseFile" attribute, which appears to be from the deduplication of the file.
When the Macs attempted to download a "sparsed" file they get an error along the lines of "you do not have permissions to copy this file". This is annoying enough, but the biggest head ache is when a user tries to copy a folder that has sparced files in it, the folder and its files are seemingly copied but the Mac does not copy the sparced files... and give no indication to the user that it ran into an error... Finder just closes like the operation was completely successful.
Even more annoyingly the user can open the file directly from the server, and work on the file with seemingly no issues, but when they save the file the changes are often not saved, and the user gets NO feedback from the application or OS.
It seems the Macs are seeing the file as having a NULL file size and they skip the file when they download it. This was not the case in 10.9.1 or any other version of any other OS we have tested. We have entered this as a bug to Apple and hope they will fix it... mostly just posting this for the next admin who is pulling his hair out trying to figure this out.
For a work around you can force the Apple 10.9.2 system to use SMB1 by using the CIFS protocol to connect to the server instead of normal SMB... which is not ideal but will work for now.