Microsoft has warned that a critical security patch for Windows Explorer released last week could crash Office applications or prevent access to files and folders.
The software firm had already been criticised for delaying its release of a security patch for the Explorer vulnerability, when hackers were already circulating code to exploit the bug.
The patch causes problems for users of Hewlett-Packard scanners, cameras, Deskjet printers with card readers and HP’s Share-to-Web and Photosmart software, Microsoft said in a notice issued on its support website. Users of Sunbelt Kerio Personal Firewall could also experience problems with Windows.
Affected users could find themselves unable to access or open Office files in special folders, including the "My Documents" folder. Office applications may stop responding if users attempt to save or open Office files in the "My Documents" folder.
Users may also find that typing a website address into the Internet Explorer address bar or clicking the plus sign beside a folder has no effect, Microsoft warned.
The problems have arisen because the HP software prevents a file - VERCLSID.EXE - included in the patch from working properly. Microsoft suggested users of HP products should make manual changes to the registry, while Kerio users should configure the firewall to allow VERCLSID.EXE to execute without prompting.