Top German-based software security vendor apologised after an update for its paid anti-virus program caused Windows PCs around the world to malfunction.The affected products are Avira Professional Security, Avira Internet Security 2012 and Avira Antivirus Premium 2012.
A service pack issued on Monday caused its ProActiv behavioral monitoring component to block a number of important Windows executable files including cmd.exe, rundll32.exe, taskeng.exe, wuauclt.exe, dllhost.exe, iexplore.exe, notepad.exe, and regedit.exe. Some online report claims that even programs such as Microsoft Office, OpenOffice, Google Updater, and the Opera Web browser have also been blocked after the update was installed.
Avira responded by withdrawing the malfunctioning update, Service Pack 0 (SP0) for Avira Version 2012, and issuing a replacement upgrade. The advisory can be found here.
Users who can’t get their PCs to boot are advised to start Windows in Safe Mode and disable ProActiv.
Certain reports suggest that over 70 million users are affected by the update. This however does not affect the free version of the Avira Anti-Virus program as it does not include the ProActiv feature.