I upgraded 3 sites on weekend from 1.12.1 -> 2.0 -> 2.0.1.1 and all sites have this same issue. I'm looking for any hints where to start debugging this issue.
I can update templates and settings, but when I try to save page I get this:
![Image](http://pics.hasanen.net/2015-11-25-18-05-24-6cdsr.png)
Is it possible that some module cause this?