A bad import is recoverable when you planned for it.
Every so often, something slips through, a wrong AutoFix guess that looked fine at a glance, or a workbook edit that turns out to be off. The instinct is to try and patch it live, chasing the fix with another fix. Resist that. It’s almost always cleaner to restore.
Restore takes you back to your last backup, cleanly, in one step. From there: correct the workbook properly, validate again, and re-run the import. It sounds slower than patching in the moment, but it’s usually faster overall, and a lot less stressful, because you’re never building on top of a state you’re not sure about.
This is exactly why backup at the start matters so much. It’s what makes this option available at all.