...it continues after a while, so maybe it is running into some timeout. Seems to be an selinux issue; it happens in enforcing mode, but not in permissive mode. With metacity-2.15.5-6 and selinux-policy-2.3.1-1
Would you say this is a duplicate of bug 197910 ? You mention that it continues after a while, does metacity eventually start successfully?
Fixed in rawhide, as far as I can see.