I installed the update packages by Windows Update yesterday, but after I finished the installation, rebooted my system, I found that some of my user settings, such as file associations, icon sequence in the system tray and etc. were reset. What's more, I wasn't able to change the settings with my account.
But the strange thing was that if I start a program with the Administrators privilege, I could again change the settings.
It seemed to be a problem on user privileges so that I checked the detailed contents of the packages and found KB3021674 did some fix on user profile permissions. So I rolled back my system, installed all other packages, and this time there weren't problems.
Finally I tried installing KB3021674 again via the package provided in https://www.microsoft.com/ja-jp/download/details.aspx?id=45431 , as expected, the problem came out again.
Is it a common problem or my personal one? How to fix it? Thanks.