The issue must be caused by one of the following patches:
The effect is that users can navigate to any UNC ressource when klicking their way through windows explorer. The same UNC path pasted into the address field causes an error.
VB Scripts accessing those ressources also fail. So does sending a PDF file (located in a subdirectory of a user's home drive) through AcrobatReader's send function.
I will investigate which of the updates causes the problem as soon as possible.
Edit 20150717 / 9:05h: Windows Server 2012R2 does not exhibit the problem.
Edit 20150717 / 11:13h: Removed all of the above form one of our 2008R2 terminal servers. Still no joy. Will remove OfficeUpdates next.
Edit 20150717 / 14:33: Temporarily solved by making the full path to the target directory browseable. Example: \\myserver\myshare\allhomes\myhome\somedir\someotherdir
Typing that path into Windows explorer resulted in an error. "allhomes" was not readable by the client. Making that readable fixed the user's problems.
Strangely enough \\myserver\myshare\allhomes\myhome worked without the modification.
Edit 20150717 / 17:32: We're still scratchig our heads about this. Our terminal servers still had the problem after uninstalling all of the above KBs. Making the whole path readable helped.
While another highly production-critical server was OK after removing them (and reboot).
Edit 20150720: We'll stick with the workaround: Make the whole path browseable. I'm not quite happy with that, but too much time has gone into that already.
Edit 20150721: Applied patches on another production machine. Also resulting in access probems. (Detail will follow)
Edit 20150722 / 14:50
EMC does not seem to have anything to to with our production problem. We're running a production-critical piece of software (and: yes, we have two them, of course) on a win2008r2 server . The software manufacturer came back to us this morning with new info:
The following patches must not be installed:
Security Update for Windows Server 2008 R2 x64 Edition (KB3067505)
Security Update for Windows Server 2008 R2 x64 Edition (KB3057154)