Comment 16 for bug 1301125

This started to happen for me occasionally after the upgrade to 14.10 (so it did not happen for me in 14.04).

Either the lockscreen does not yet appear (and it shows a frozen buffer of the last view of the desktop), or it shows the lockscreen, but doesn't respond to keyboard (password input) or mouse clicks. Closing the laptop lid does not go back to stand-by but keeps the frozen screen on. I have to do ctrl+alt+f1 and restart the session.