The day is yet young, but I'm seeing lots and lots of reports of crashes, hangs, and odd behavior attributed to KB 3097877. As of this moment, Microsoft hasn't acknowledged any problems in KB 3097877, and the only surefire workarounds involve uninstalling the patches or rolling back to an earlier system restore point.

Here's the short version.

KB 3097877 is part of security bulletin MS15-115, which is (yet another) critical patch to fix vulnerabilities in OpenType fonts. This KB is specifically for all supported versions of Windows (including Windows RT and RT 8.1) except Windows 10.

There's a lengthy series of network logon complaints on the TechNet forums, led by poster Asomodai, who reports:

We are no able to log in a significant amount of computers, this also happens in safe mode where upon pressing control alt delete for login it turns to a blank screen with just a mouse cursor.

Poster dfertig continues:

I have 5 reported computers that just get a black screen after hitting Ctrl+Alt+Del, we can't log them into the domain.... The computers that this has happened to in my domain are all Windows 7 64 bit that are configured to download and install all critical windows updates overnight. (I'll likely be looking into setting up WSUS after this) We have about 150 computers and only 5 have been reported so far with this problem, I know for a fact that a lot of computers were just shutdown over night so they are likely downloading updates this morning automatically. This sucks....

There may be a solution for some systems: Unplug the network cable and/or unplug the touchscreen USB cable and/or disable the touchscreen by whatever means. Details are in this Reddit post.

The same botched patch is blamed for a specific set of symptoms with Outlook 2010 and 2013. Also on the TechNet forums, poster TrulyVexed says:

Was finding that specific e-mail were consistently causing Outlook 2010 and Outlook 2013 to crash. They were always HTML messages, typically the sort of "on sale" e-mail you get from distributors etc that include a lot of tables, images etc.

Poster BenC1977 adds:

I'm getting the same problem with Outlook 2010 32bit on Windows 7 64bit, it's only affecting some HTML emails but as soon as you select one in the list I get the error "Microsoft Outlook has stopped working". All these emails were working fine yesterday so the updates are to blame.

On a different TechNet thread, SRC-UK says:

Installing this update today resulted in APPCRASH AususAudioCenter.exe (App ver 0.3.0.36) ntdll.dll relating to my Asus DX Xonar Sound Card on a Windows 7 64bit Pro Desktop PC. Was able to restore to pre-update state no problem. Was able to replicate this issue a few times. I see a few others are having similar problem with the sidebar regarding this update. Microsoft, please investigate/rectify!

Yet another TechNet thread says the same KB also kills Windows 7 Sidebar gadgets (which were deprecated by Microsoft before Windows 8 arrived). Poster Asghan86 says:

Windows Sidebar Gadgets Stop Working After November 2015 Updates / As soon as KB3097877 is installed, sidebar.exe crashes during launch. Uninstalling KB3097877 immediately solves this and sidebar.exe works again. OS is Windows 7 Prof, x64 and x86 affected.

A little gedanken experiment, if you will. What happens when the same sort of mayhem breaks loose on Windows 10 systems, and you can't prevent Windows from installing the bad patch over and over again (or the method for doing so requires a BA in Computer Science)? If the only real solution is for Microsoft to yank the bad patch, how long will it take Microsoft to pull the update? So far this morning, the real-world results aren't very heartening.