Users who installed Microsoft's latest round of security patches may be experiencing some unexpected computer instability and even system crashes. Microsoft said that its security update MS06-015 may cause several problems with Microsoft Office, Windows Explorer and Hewlett-Packard's Share to Web software. The root of the problem seems to be a new file installed by the update, VERCLSID.EXE.

Both HP's software and Sunbelt's Kerio personal firewall can stop the new file from working, which in turn causes the rest of the system to become unstable. VERCLSID.EXE checks shell extensions and makes sure they can be run by Windows Explorer or the Windows Shell. In some cases, the check may inadvertently fail. Microsoft says users may be unable to open the"My Documents" or "My Pictures" folders and may experience crashes when trying to open files. Other users may be unable to type in addresses into Internet Explorer, along with being unable to expand folders in Windows Explorer.

Microsoft has released Knowledge Base article 918165, which detail two new fixes. The first is for users of Hewlett Packard's Share-to-Web software. Those users can enter in a registry key to stop VERCLSID.EXE from scanning some HP-related files. The Kerio personal firewall sees VERCLSID.EXE shell validation as being spyware-like and flags it for further investigation, which causes some of the system crashes. The knowledge base article advises Kerio owners to set up an exception list that ignores the file.

Microsoft has not announced if and when it will be issuing a patch for its patch. MS06-015 was released last week to fix a critical security flaw in Internet Explorer. That flaw, when exploited, would give hackers the ability to gain remote control access to a computer.