Not that most of you are going to ever see this or care, but as for me, I just spent about 6 hours over the last few weeks trying to resolve it so I hope as a public service this will help someone both fix their client and save some time!
Background:
My Ubuntu owncloud client was working just fine on my netbook. Then I made a change to the server where the URL changed where owncloud was hosted. On one machine, I simply booted up owncloud, changed the setting and everything worked. On the other machine, it would not forget the former URL and something went wacky inside. I hope you like my terminology. Anyways, I took the time and courage to just start trying to delete everything from my netbook related to owncloud and reinstall but that didn’t work either. Finally, this is what worked (assuming you have opened a terminal window):
1. sudo apt-get purge owncloud-client
2. sudo apt-get autoremove owncloud-client
3. go to your home folder and totally delete the owncloud folder (make sure you save anything that might be in it and not synced to your server!)
4. KEY STEP
a) cd /tmp
b) ls
You should now see at least one directory that starts with sni-qt_owncloud_3658-HTGzH (or something along those lines). In my case, I had many of them which I thought to be a problem. So, I deleted them all and this was the step that fixed everything. How to delete?
c) rm -rvf sni-qt ….
d) repeat steps ‘b’ and ‘c’ above until all traces of these sni-qt directories are *totally gone*
5. Reinstall owncloud-client
sudo apt-get install owncloud-client
NOTE: It’s probably better, although I didn’t try, to instead open your software centre and install it from here. I found my icon didn’t show up using the command line here in the terminal…. sup to you….
6. start owncloud by just typing ‘owncloud’ or by searching for it the normal way you open programs.
7. go into your ‘settings’ and make sure your server settings are correct.
Everything should now be working
Hope that helped and if you have time and energy please file this blog with the owncloud open source team. I ran out of time….