The other way that that message appears ("this is usually caused by resuming an already-complete backup, or by your site having a faulty object cache active (e.g. W3 Total Cache's object cache)") (other than having a faulty caching plugin) is if your backup ran out of time. That can happen on development sites that are rarely visited. To prevent it happening, visit it every 5 minutes (or set up an automated task to do so).
David
↧