&gt;<i>Huh. The Time Machine preference pane suggested that I try again later, and I did, with the same result. Since there was an error creating a folder, I guessed that the disk might have some errors, so I ran Disk Utility. Sure enough, there were errors, but Disk Utility couldn’t fix them. Neither could DiskWarrior. Or TechTool Pro. So I was left with no choice but to reformat the disk and start over from scratch. I still don’t know what caused the problem, but neither Time Machine nor any disk utility I tried could fix it—and the hardware itself was, as far as I could tell, just fine.</i><p>The last sentence makes absolutely no sense. He said Disk Utility found errors, but couldn&#x27;t fix it, and neither could DiskWarrior and TechTool Pro. So clearly the hardware itself was NOT &quot;just fine&quot;.<p>&gt;<i>When my backups become suddenly inaccessible for unknown reasons and I’m offered no solution but starting over, that sort of diminishes my faith in the software.</i><p>In light of that, what should Time Machine have done? Magically fixed a disk 3 specialized disks couldn&#x27;t fix and continue?<p>What would ANY other backup software do?