I began 2017 with a pair of columns reminding users that their hard drives are going to fail—absolutely and positively—and that the question isn't if they're going to fail, it's when they're going to fail. And, I urged them to back up their data or risk losing it forever. If you haven't seen the columns already, you really should; you can find them here:
Resolve to Back Up Your Mac in 2017 (Dec 28, 2016 ) & Backups on a Budget (Jan 04, 2017).
Go ahead; I'll wait...
And now, here's the thrilling conclusion (at least for now):
My Time Capsule is Headed for the Trash Heap!
I started getting this error message occasionally a few years ago... But I saw it frequently enough last year that I reformatted my Time Capsule drive and started from scratch, hoping that would fix things.
It did not. Last week I saw this disappointing error message for the third and final time since reformatting... Now, I've lost my trust in the Time Capsule and its hard drive so it's headed to the scrap heap RealSoonNow™.
As you may recall, one of the things I stressed in those two columns was that you absolutely, positively must test your backups by occasionally restoring some or all of their files. Remember: A backup you can't restore from isn't a backup at all.
Frankly, this was no big deal to me—my other nickname is Dr. Redundant. That Time Capsule backup disk was one of three local backups I maintain, along with a cloud-based backup (using Backblaze), and two sets of clones (I use Carbon Copy Cloner and ChronoSync): one stored locally; the second stored at my bank in a safe deposit box.
The point is, had the Time Capsule been the only backup I had, I'd have no backup at all today!
So make a backup plan and test it relentlessly. Just do it. Please.