Forgetful Time Capsule
My MacBook Pro (Mid 2015) backs up to a Time Capsule. Recently, it started warning me about once a week that backups have verification problems, and informs me that it must create a new backup. It then wipes all my old backups and starts again. How can I stop this?
Your Time Capsule is detecting that its previous backups are corrupted beyond repair, so it must trash them and start afresh.
If this occurs once, it’s worrying, and when it happens repeatedly there must be something seriously wrong with your Time Capsule.
Ensure its firmware is fully up to date by opening AirPort Utility and inspecting the Time Capsule there. Click any red badge next to it there for details, update as needed, then initialize it from scratch.
If, after that, your Time Capsule repeats this behavior, it shows that something is corrupting the hard disk in it, or that the drive is sick and failing – which is a matter for Apple Support, or a Genius Bar. If it’s older than three years, you may need to replace it.