Microsoft has pulled an update for Outlook 2007, which was issued just two days prior to being pulled, citing connection and performance problems for the unusual move.
The update was issued on December 14 as part of the monthly Patch Tuesday. Within hours, users reported trouble with retrieving email 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 'alspar' on a Microsoft support forum. "Is this an error or by design?"
Others said they couldn't send or receive email, 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".
Within days support forum moderators were telling users to uninstall the update.
Microsoft made that official in a post on the Outlook team's blog. "We have discovered several issues with the update and... as of December 16, this Outlook 2007 update has been removed from Microsoft Update."
According to Microsoft, the update contained three flaws related to Secure Password Authentication (SPA), a Microsoft protocol used to authenticate mail clients like Outlook to a mail server; sluggish folder switching when Outlook wasn't configured to grab mail from an Exchange server; and a broken AutoArchive feature.
Microsoft urged users who had installed update during its three days of availability to remove it, and spelled out the necessary steps.
The company also issued a mea culpa.
"We apologise to our customers for not discovering these issues before releasing the update and for any inconvenience we have caused," the Outlook team said on its blog.
"We failed to meet our own and our customers' expectation for quality with this update release. We are working to fix these issues and will post a release date for those fixes, and link to download them, as soon as that information is available."
Microsoft has yanked updates before. In April, it pulled a patch for Windows 2000 - which at the time was still being supported - over what it called "quality issues".
In early 2008, Microsoft retracted an update designed to prep Windows Vista for Service Pack 1 (SP1) after users flooded support forums with tales of endless reboots.
Microsoft has not set a timetable for releasing a re-patch for Outlook 2007.
See also: Microsoft pulls bad Windows patch