Indeed I found that CTRL+ALT+F1 then ALT+F7 allowed me to come back to my session, but with some features sometimes not working (http access with firefox, task bar in kubuntu...).
I upgraded to Kubuntu 13.10 Beta 1 (this page: http://www.kubuntu.org/news/kubuntu-1310-beta-1) at the beginning of the week. From that moment I had no more trouble with this issue -- hopefully it won't come back.
Indeed I found that CTRL+ALT+F1 then ALT+F7 allowed me to come back to my session, but with some features sometimes not working (http access with firefox, task bar in kubuntu...).
I upgraded to Kubuntu 13.10 Beta 1 (this page: http:// www.kubuntu. org/news/ kubuntu- 1310-beta- 1) at the beginning of the week. From that moment I had no more trouble with this issue -- hopefully it won't come back.
Maybe upgrade?
Marc