A month just can't go by without reports of botched Microsoft Updates. We've had a couple this month (KB2984972 breaks App-V packages and KB2995388 causing issues with VMware workstation), with one that was pulled, but this seems to be the norm these days. Clearly, we're at the point now that if a Patch Tuesday went by without problems, we'd believe something was wrong.
But, even with October's Patch Tuesday a couple weeks behind us, and only one more day before October 2014 is completed, there's one additional update to worry about. It almost seems like a Halloween trick, but it's not.
In a bunch of reported cases, installing KB2986204 breaks the offline address book download in Outlook 2013 when using MAPI over HTTP. There's a well-populated thread describing the problem in the Microsoft forums. Check it out here: KB2986204 breaks Offline Address Book download using MAPI over HTTP.
The ironic part here is that KB2986204 was released to fix an issue with Outlook not able to connect to the Exchange server using the MAPI over HTTP protocol.
The thread ends with a Microsoft rep admitting defeat on this one, stating that Microsoft will supply another fix in the November updates, and offering instructions on how to uninstall KB2986204.
Happy Halloween! I hope the Great Pumpkin rises from his pumpkin patch for you this season.