I have a few hundred PCs (all Windows 7) that ran auto updates the night of 7/11. One of the updates that was installed was KB2691442. The install of this update has stopped an interaction between the PC and an emulator used to connect to a Unix server. Prior, the PCs would use an emulator to connect to an AIX server running a third party software. During start up of the emulator/software, a batch file is run to make sure the end user can access the server shares via hostname. If they can, a switch is turned on for that user so that 'create PDF' is a print option. When creating a report the user has a print menu in which they would have a choice to view a report 'as pdf'. Once the PDF choice was made in the emulator, the emulator would run a pre-determined program that tells the PC where the PDF is (file location and file name) and that the PC should open it. Since KB2691442 (and doing debugging in the program) we've determined the initial batch program runs and its determined that the PC has access to the shares but the command to open the PDF file is not received by the PC.

I would 1. Uninstall update wusa /uninstall /kb:2691442 2. Contact MS Support and report bug 3. Troubleshoot update on test machine. 4. You have not given any data on how PDF files are opened. If Adobe reader is the case, then play with Preferences (Internet > Display PDF in Browser etc). If nothing help (or at the same time) ask in Adobe support forum. 5. Process Monitor may help you to resolve the problem Regards Milos