Better work-around is, as metioned by Philip Langdale, editing the file /etc/apparmor.d/usr.bin.evince like this (insert the nameservice-line):
/usr/bin/evince-thumbnailer { #include <abstractions/evince> #include <abstractions/nameservice> : -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to evince in Ubuntu. https://bugs.launchpad.net/bugs/778638 Title: evince-thunbnailer gets permission denied from apparmor (and hangs the system for long periods of time) -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs