This bug has plagued me for the last two years or so, on a variety of E versions.
This happens rarely (once a week or so).
The effect is that E stops updating the screen (except for the mouse position&shape, see below) -- the currently visible app updates stop as well.
However, input is still processed, apparently, since I'm able to change virtual desktops -- which I only know, because the mouse pointer changes shape due to the type of window it's hovering on.
I can get things unstuck, by switching to a VT and issuing DISPLAY=:0 enlightenment-remote -restart -- after a while everything becomes fine -- apps are back and all is well.
Until the next such freeze.