I liked the DiskDigger un-delete program.  Out of the four un-deletion programs I recommended here, DiskDigger was my first choice.

Fast forward to now.

I stupidly deleted a temp file on a USB memory disk, and needed it back.  So I downloaded a copy of DiskDigger.

Not very happy now.

DiskDiggerWithout a license key, DiskDigger will pop up an annoying message box that gently reminds you to purchase a key. It does, of course, allow you to continue without a key, and even proceeds to recover your files.  However, it will keep popping up the message box for every file you’re trying to recover.  So just buy a license key already!  It’s a lot less expensive than comparable utilities out there.
DiskDigger FAQ

Hey, I’ve got no problems in buying a license key, even if the program is “free” for personal use.  I do have a problem with a program which introduces a five second delay “nag” screen for every file it wants to recover.

There is no way in heck I’d ever recommend DiskDigger now.

As alternatives:

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