The El Reg inbox has been flooded with reports of a serious cock-up by Microsoft's patching squad, with one of Tuesday's fixes causing killer problems for Outlook.
"We are looking into reports from some customers who are experiencing difficulties with Outlook after installing Windows KB 3097877. An immediate review is under way," a Microsoft spokesperson told us.
The problem is with software in one of the four critical patches issued in yesterday's Patch Tuesday bundle – MS15-115. This was supposed to fix a flaw in the way Windows handles fonts, but has had some unexpected side effects for some Outlook users.
"Today I've deployed latest Outlook patch to all of my clients, and now Outlook is crashing every 10 minutes and then restarting itself. I tried on fresh Win10, no AV with latest patches applied and here we go, Outlook crashing there too," complained one TechNet user.
"Come on guys, do you EVER do proper QA before releasing anything Office 2013 related? This is the worst version of Outlook ever. Sorry for negative attitude but this is how things are."
The break point appears to come not when an email that contains certain fonts is opened, but when it's scrolled through. Outlook 2010 and 2007 seem affected, but the issue is reportedly fixed when the patch is uninstalled.
The SysAdmin sector of Reddit is awash with reports of problems with the patch, and it appears to be a cross-OS problem. The general consensus is to disable the patch on Windows Server Update Services and wait for a reissue.
But millions of consumer users could be in for a nasty shock when Windows prompts them to download yesterday's patches. Anyone relying on Outlook for their email is in for a nasty surprise. ®