Comment 67 for bug 564181

Immediately after upgrading to Kubuntu 10.04 AMD64, the system would enter this video loop symptom as described after login and as items were added to the system tray. I removed several packages (hplip-gui and kdebluetooth) that load into the system tray and it had no affect.

I booted into recovery mode as root and started X. It came up but was notified that Nepomuk needed Virtuoso and that there were some missing language files. I corrected the missing language files and installed the virtuoso-server package, and then was able to login without the system going into this loop mode for several hours.

When it did enter the video loop state again, it occurred immediately after I removed a USB flash drive. It does not happen consistently as I was unable to reproduce this. This parallels bugs 568605 and 565323. I hope this provides some clue as to what's happening.