I just tried to launch deluge and got the following error:
progname=deluge; RGBA=on
Traceback (most recent call last):
File "/usr/bin/deluge", line 9, in
load_entry_point('deluge==1.2.1', 'console_scripts', 'deluge')()
File "/usr/lib/pymodules/python2.6/deluge/main.py", line 121, in start_ui
UI(options, args, options.args)
File "/usr/lib/pymodules/python2.6/deluge/ui/ui.py", line 128, in __init__
ui = GtkUI(args)
File "/usr/lib/pymodules/python2.6/deluge/ui/gtkui/gtkui.py", line 216, in __init__
self.torrentdetails = TorrentDetails()
File "/usr/lib/pymodules/python2.6/deluge/ui/gtkui/torrentdetails.py", line 116, in __init__
state = self.load_state()
File "/usr/lib/pymodules/python2.6/deluge/ui/gtkui/torrentdetails.py", line 432, in load_state
state = cPickle.load(state_file)
cPickle.UnpicklingError: could not find MARK
Deluge would just crash and would not show up at all.
I tried searching for a solution, but did not find any. I tried upgrading to the ppa version of deluge with no luck. Then I just removed all the .state (not to be mistaken with state directory) files (peers_tab.state, files_tab.state, torrentview.state, tabs.state, dht.state, session.state and any other file containing .state at the end) from /home/MyUserName/.config/deluge and was able to launch deluge again. You should not remove the state directory because you will lose the torrent list if you do.
After that, you will be able to launch deluge. It is a good idea to recheck (Right click on a torrent file and select Force Recheck) all torrent files after you do this.
Hope this helps.