for some reason, the GUI interface to defraggler crashes whenever trying to perform a full defrag on a drive (any drive)... it used to work, but at some point stopped working, for no obvious reason (no new version of defraggler installed, etc)... the crash occurs almost immediately after the actual defrag begins (analysis runs fine, crashes in defrag process)
i decided to test and see if it also crashes when using the command line interface, and discovered it DOES work from the CLI.
/debug3 logs dont provide any insight (to me, at least)... is there anything i can do to troubleshoot this? should i upload the debug logs from the GUI/CLI/both?
As Nergal says, but after posting those, something you could try in the meantime is a re-install of Defraggler.
There are two separate executables in Defragglers "Program Files" (XP location) folder, "Defraggler.exe" (GUI version) and "df.exe" (command line), and df.exe working fine suggests you may have a problematic Defraggler.exe.
If you have a problem doing that, you could try manually deleting Defraggler.exe in case it's corrupt (and may not be overwritten by reinstalling), and see if it then works as it should.