1. fully operational or working properly again
it was broken, but now it's back up and running
If something is 'up and running' it means it is operational and functional. This expression is usually used to talk about machines and computers working correctly or being online. If something is 'back up and running' it means it was previously not working properly but now it has returned to being in full operation. If someone has been sick you can also say 'you'll be back up and running in no time'. This is a casual expression used in both professional and social contexts.