Windows fix in patch of bother

A "critical" Windows patch can cause trouble on computers that run certain HP photo-sharing software or the Kerio firewall, Microsoft said.

The MS06-015 patch, designed to plug a flaw in Windows Explorer, can cause a myriad of problems for users of HP printers, scanners and digital cameras, Microsoft said in an article on its support website. People with Sunbelt Software's Kerio Personal Firewall will also notice that Windows no longer works as it should after applying the fix, Microsoft said.

The problems include being unable to access or save files in special folders like "My Documents" and "My Pictures", and unresponsive Office applications, Microsoft said. Other issues include applications that crash after trying to open a file; no response after typing an address into Internet Explorer's address bar; and no effect after right-clicking on a file and selecting "Send To", Microsoft said.

While designed to fix a security issue in Windows Explorer, the patch can actually also impair that specific Windows feature. Clicking on the "plus" sign beside a folder in the file browser may have no effect, Microsoft said. That action should expand the directory tree.

The problems occur because HP's "share-to-web" software and the Kerio firewall interfere with a new file - verclsid.exe - delivered by the security update, Microsoft said. The HP software in question ships with cameras, printers, scanners and some DVD drives, Microsoft said.

Microsoft recommends affected users of the HP products manually change their Windows Registry, a core part of the operating system that stores PC settings. Kerio users should configure the firewall to allow the new Microsoft file to execute without warning, it said.

The Windows Explorer update isn't the only patch in Microsoft's latest round to cause trouble for some users.

The Windows Explorer fix was one of five updates Microsoft pushed out last week as part of its monthly "Patch Tuesday". Some people had already reported trouble with the IE fix, which changes the way the browser handles ActiveX Web applications. Users of Siebel's business software, in particular, appear to have been hit hard.

Joris Evers writes for CNET News.com