Public bug reported:
I upgraded my system from Dapper Drake to Edgy Eft. After I log in into
Gnome, Metacity fails to load. If I start Metacity manually, it works
ok.
** Affects: metacity (Ubuntu)
Importance: Undecided
Status: Unconfirmed
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Metacity doesn't load after login
https://launchpad.net/bugs/63185