Office 2010 patch KB 3114750 clobbers Outlook Calendar (again)

On Feb. 9, this month’s Patch Tuesday, Microsoft released an enormous array of Office patches — 79 separately identified patches, including 26 designated security fixes (all part of MS16-015) — as well as new versions of Office 2010 Click-to-Run, Office 2013 Click-to-Run, and Office 365 Click-to-Run. One of those patches, KB 3114570, re-introduces a retrograde bug in the Outlook 2010 Calendar.

The KB 3114750 article describes three fixes:

• An Office add-in that overrides the default functionalities, such as copy or paste, and uses a delay loading can’t be loaded in Office 2010 applications.
• When you use the Save As function to save a document to a WebDAV server in an Office 2010 application, the Office 2010 application may crash. This issue occurs after you install October 13, 2015, update for Office 2010 (KB3055034) or a later update for Office 2010.
• You use SharePoint Workspace in a time zone that does not observe daylight savings time (DST). You apply KB3101521 to Microsoft Office 2010. After the update, when you try to open or create a workspace, you receive one of the following errors:

Tool cannot be displayed.

legacy localized error message.

The parameter is incorrect.

The KB article doesn’t mention that this patch brings back a bug last seen in the Jan. 12 patch KB 3114570. (Warning: The numbers are very similar, but the patches landed a month apart.) That bug, as I documented last month, was the latest manifestation of an error that had appeared even earlier.

In January, poster Jon999_ in the Microsoft Answers forum described the bug as follows:

After the [KB 3114570] update is installed, Calendar appointments that span midnight (ie, appointments that start on one day before midnight and end the next day after midnight) appear in Day and Week calendar views as if they were all-day appointments, as a small bar at the top of the day column instead of covering the appropriate hours. Additionally, the end time of such appointments shows up wrong (as 00:00, regardless of the actual end time) in all views including Month view. Prior to this Update, such appointments of

It’s happening again, even if you uninstalled the old KB 3114570.

At the time, a month ago, Microsoft employee Gabriel Bratton promised:

I just wanted to update that we provided your feedback to the product team and they have decided to revert the change back to the way it worked previously.  If everything goes as expected we should see the issue addressed for Outlook 2010 in the March 9th public update.

It’s still too early to tell if the March 9 version of the patch will, in fact, go back to the old way of working. What we do know is that the Feb. 9 Office 2010 patch clobbered it again.

If you got bit, the only solution is to uninstall this new patch.