In August, Microsoft issued their Windows 10 Anniversary Update, which result in some problems for users around the world, notable with the operating system locking-up or freezing (see this Reddit thread as an example).
As a result of the issues, Microsoft issued a series of hotfixes and updates, culminating in a Cumulative Update KB3176938.
However, since its release on August 31st, 2016, KB3176938 has given rise to renewed Windows 10 / OpenGL issues which are impacting a number of games – and also impacting Second Life.
Whirly Fizzle has raised a JIRA on the problems – BUG-37795 (based on a Firestorm filing by Vicky Aura (FIRE-20034). The issue is intermittent, but when encountered, results in exceptionally low FPS rates (on the order of 1 or 2 fps). The issue tended to occur when moving focus away from Second Life to another running application, and then switching back. Whirly reports that on some systems this problem is intermittent but on other systems it will reproduce after the viewer has lost focus for the first time in a session.
The issue has also been raised on the Microsoft forums by Firestorm developer Ansariel Hiller – but do note, the issues is not related just to the use of Firestorm, other SL viewers can be affected.
Currently, if you are a Windows 10 user and being hampered by this issue, the only known workaround is to uninstall KB3176938. Again, as Whirly points out in the JIRA, How To Geek provides instructions on how to do this – and please refer to the comment from Torric below, when doing so.
Again, please note this is not a Second Life problem, it is an issue within Windows 10 affecting assorted applications and games using OpenGL.
With thanks to Whirly Fizzle.