You’ll see this message if your File History drive has been disconnected for too long. If you’re backing up to an external drive (like a USB drive), make sure it’s connected to your PC. If you’re backing up to a network location, go to Settings > Update & security > Backup and reselect the network.
After you’re reconnected, wait for the next scheduled backup or start a backup manually by selecting Settings > Update & security > Backup > More options > Back up now.
