Red Triangle.....Waiting for Apt-get to Exit

Red Triangle

Problem a RED Triangle has appear near the clock at top screen saying:-

The update information is outdated. This may be caused by network problems or by repository that is no longer available. Please update manually by clicking on this icon and them selecting 'Check for updates' and check if some of the listed repositories fail.

If I click on it or first try manual update I get:-

Waiting for Apt-get to Exit

I am unable the update either auto, or manual.

Please help