Why doesn't my Auto-backup or upload keep running in the background?

On iOS 7 and 8, apps are generally allowed to run in the background for up to 10 minutes; this is by design, so the app does not consume your battery while it's not being actively used.

If you are uploading a large file, running auto-backup for the first time, or casting a movie to your TV with Chromecast, you will want to keep the app open in the foreground to avoid interruptions.