I was not able to install Windows 8.1 Update for x64-based Systems (KB2919355), For a last few months. It's not like I was trying to do it everyday, simply when I noticed that I am not able to install it I tried again after few weeks. Unfortunately this update is required for me to install other update that is required to play with new
.NET 4.6 preview framework (link to Visual Studio 2015 download, because that's the place that allowed framework to be downloaded).
What didn't work
Using File System Checker to repair missing or corrupted system files
sfc /scannow
Running in cmd as Admin following commands
net stop wuauserv
net stop bits
net stop cryptsvc
ren %systemroot%\System32\Catroot2 Catroot2.old
net start cryptsvc
ren %systemroot%\SoftwareDistribution SoftwareDistribution.old
regsvr32 wuapi.dll
regsvr32 wuaueng.dll
regsvr32 wucltux.dll
regsvr32 wups2.dll
regsvr32 wups.dll
regsvr32 wuwebv.dll
net start bits
net start wuauserv
net start Eventlog
exit
What resolved the problem
Running in cmd as Admin following commands
DISM.exe /Online /Cleanup-image /Scanhealth
DISM.exe /Online /Cleanup-image /Restorehealth
DISM process failed few times when I run it.