This update was disturbing me a long time and today I decided to fix it.

This update was failing with a configuring error after installation so it was not possible to install it the usual way - here is the reason and solution for it:

I am using a RAM Drive for my TEMP Directory just because my SSD (where the system is on) should not care about useless space loss.

Now, the thing with RAM Disks is, that they are removed, when windows is restarting, so everthing in there is lost.
For whatever reason the mentioned Update KB2685811 does depend on some files which are stored in the TEMP dir .. while that is a bad idea (maybe some devs ad MS never heard of RAM Disks) for update installation it is easily fixed by just deactivating the RAM Disk (or only move back the TEMP dir to original location), install the update, restart and reactivate the RAM Disk

Problem solved.

This happens from time to time but hopefully in the future, devs will respect non-permanent TEMP Dirs... ironically, even MS states in many docs, that there is no guarantee, that files in TEMP Dir will survive a reboot, so it is a bit of dumb, when they use it for their own updates :-)