Difficulty running "Debug"

Newbus Ignoramus here:

I have followed the debug instructions pinned here a number of time. The result is that Defraggler opens with no "Debug" shown. The reason for me running "debug" is that when I run Verify, Defraggler can't finish and asks if I want to run checksum. I check yes, restart, and everything is okeedokee. I then rerun Defraggler and get the same result.

Huh?

Garibaldi