[SOLVED] Errors preventing shutdown and program execution

Hi, I am using this system which uses xfce, and I think I am in the right place for questions. http://zedboard.org/product/zedboard

My system was working fine until recently I received two errors, one at start up saying

Failed to set new theme Failed to write file '/home/analog/.cache/xfce4-notifyd-theme.rc.161GAA': write()failed: No space left on device

and another when I try to shutdown or logoff

Received error while trying to log out Session manager must be in idle state when requesting a shutdown

I noticed that my root is 100% full when I check space, but permission is denied when I try to access it. Could this be the problem?
Please provide suggestions as I am stuck at the moment. I haev screenshots of the errors but I cannot upload attachments. Thank you.

Hi and welcome to LQ.

Yes, a big deal is the "no space left on device" report there.

How are you logged in? As root or another user? Are you able to access the command line? Look at your disk space which partitions are 100% and see if there are things like cache or other files which can be safely deleted to free up space. Other issues are that we don't know how long your system has been running and what's been done with it. This could be as simple as a bunch of internet cache files, or other temporary files, or it really could be that you have too much information in permanent files stored on your system. You also may be storing files permanently into a bad location. For instance if you are a normal user, and the root "/" partition is small because it really doesn't need to be large, but you are storing tons of personal files into that location versus a /home partition which may be much larger.

Seeing the output of "df" is a good thing to post.

Thanks for the help, indeed it was caused by a lack of space. All set now.