cannot edit after 4.2.2

Hello,

I have few issues after upgrading to 4.2.2 – cannot edit old pages and posts; cannot add new pictures to media library; I can create new page/post using only Latin alphabet, if I use Cyrillic it doesn’t work; It slows down the speed.

All plugins are disabled and it seems that it is not a Theme problem as well.

Any ideas how to solve these issues?