Back up, check the backup, then delete
2 October 2026 · 2 min read
What happened
I deleted 170,000 files in one go. Old AI experiments I had stopped using, 8 GB of them. 1,175 files were left.
Before deleting anything, I copied everything I could not rebuild to another drive. Then I checked the copy was all there: the same number of files on both drives. Only then did I delete.
I had learned that lesson the week before, the hard way.
Before and after
The risky way
“Delete everything in this folder I’m not using any more.”
→ Fast, until you find out something you needed was in there.
The safe way
“Copy this folder to my backup drive. Then tell me how many files are in each, so I can check they match. Don’t delete anything until I say.”
→ A clear-out you can undo.
Why it works
A backup you have not checked is a hope. Counting the files turns it into a fact. Opening a few makes it even safer.
This matters even more when an AI assistant does the tidying. It will do exactly what you ask, quickly. Make it copy and count first, and keep the delete for last, on your say-so.
This tip started as a post on X.