The update was issued mid-day on Dec. 14 as part of the monthly Patch Tuesday. Within hours, users reported trouble with retrieving e-mail and major delays when switching folders.

"This latest update results in Outlook 2007 being very slow in changing folders and the archiving functionality appears to have been removed," said someone identified as on a Microsoft support forum early Wednesday morning. "Is this an error or by design?"

Others said they couldn't send or receive e-mail, including Gmail messages, through Outlook after installing the update.

Ironically, Microsoft had billed the update, which didn't patch any security vulnerabilities, as one that contained "stability and performance improvements."

By Thursday, support forum moderators were telling users to uninstall the update.