After some upgrades today, I got with an unusable gnome. On every startx it failed with the window "Oh no! Something has gone wrong. A problem has occured and the system can't recover. Please log out and try again." (forcing you to close the session, just to reappear on restart)
After ~6 hours on this, and downgrading several packages to no avail, I discovered that the file /usr/share/gnome-session/sessions/gnome-fallback.session had been removed.
As I use gnome-fallback, the dconf key “org.gnome.desktop.session” contains “gnome-fallback”, and that apparently requires such file to exist
If you need to change the key with command-line:
gsettings set org.gnome.desktop.session session-name gnome-fallback
I finally got a working system by copying /usr/share/gnome-session/sessions/gnome.session to /usr/share/gnome-session/sessions/gnome-fallback.session and changing -use a text editor- its line "RequiredComponents=gnome-shell;gnome-settings-daemon;" to "RequiredComponents=metacity;gnome-settings-daemon;gnome-panel"
I hope this serves others to fix this issue.
I still miss the upper applet bar (although perhaps due to uninstalling then reinstalling gnome-panel), and key shortcuts (such as Alt-tab) are not working, but most functionality is there.
If you end up at a desktop with no menus, a way to work is to make in the desktop a symlink to /usr/bin/gnome-terminal.
this issue occurs to me just after an upgrade.
But I am not using gnome fall-back mode.
At first, the screen stopped at systemd init log screen, and stayed there for quite a time,
later the "Oh no!" screen from gnome showed up.
and after a few seconds, the normal GDM login screen appears, and I can continue...
Thanks linas, your fix (kind of) worked for me.
I'm happy it served someone.
I asked Jan, but he told me gnome-fallback is no longer supported by GNOME or Arch. Great way to destroy a desktop.
Few days ago I saw this dumb "Oh no..." message as well, however I do not use fallback mode.
I saw it after upgrade a lots of packages (including kernel, various gnome, clutter, and gtk3). Then I tried another update, because meanwhile appeared new packages, after which even GDM crashed (black screen).
In my case helpful was downgrade of kernel to 3.8.8-2 and rebuild of modules (especially fglrx (package catalyst-total 13.4-1)).
I guess nothing surprising for average catalyst & gnome 3 user...
This issue is being tracked in Bug #35240
Please vote for and participate in troubleshooting this bug if you're affected and want it fixed.
Thanks, this got most of my functionaliy back. The monitor of this computer is only used for xbmc, so as long as that works Im good. Im going to sign up for that bug.
Im a member of the testing mailing list. I dont remember reading anything about this.
I cant downgrade my kernel because I use Nvidia that depends on kernel 3.9+ and it has missing dependencies when try a downgrade that...
I apologize for my post above....it's misleading. The bug in question is regarding a similar failure with gnome, but involving the standard session, not fallback. The fallback issue may be one of deprecation, I've read that gnome was no longer supporting it as software rendering was considered 'good enough'.
So if you are having the issue described in the OP you may want to file a separate bug. I posted my bug here as a result of a quick skim of the post and replies to it. After re-reading it, I see they are separate issues.