The following post appears now on the Microsoft Security Response Center blog, in response to the disppearing Office security updates.
Information on accidental posting of pre-release security updates for Office for Mac
We've seen some questions from customers about some security updates that posted for a while today for Office for Mac that they didn't see any security bulletins for.
I wanted to let you know that these weren't security updates related to this month's release or the two Word issues we've written about in Security Advisory 929433 and on our weblog: those investigations are still underway and we'll release updates for those issues once we've met the appropriate quality bar. The updates posted in error were pre-release binaries that had been staged internally as part of our testing for an upcoming release. Due to human error, they were accidentally published to the public websites before our full testing release process was complete. As soon as we discovered the error, we moved quickly to address it and remove the pre-release binaries from our public sites. Once our investigation into this issue is complete and we have security updates that meet our quality bar for release, we'll release those final security updates for all products affected along with a security bulletin. We're also taking steps to ensure a mistake like this doesn't happen again. We recommend that anyone who may have installed these pre-release updates to uninstall them. I'm sorry for any confusion this might have caused.
*This posting is provided "AS IS" with no warranties, and confers no rights. *
Published Wednesday, December 13, 2006 2:09 AM by MSRCTEAM
Well isn't that lovely? By the way - there is no way to "uninstall" an Office update. If you did install the update that briefly appeared yesterday, the only way to revert is to restore your Microsoft Office application folder from a recent backup or just drag a fresh copy from your original Office install CD, and then apply the most recent available updates (recent as of the day before yesterday, that is). If you did install the update before it was pulled yesterday, and you don't notice any problems, you could just wait it out until the next valid update is released.