df.exe not defragging

In working on a batch file so that I can chain ccleaner with defraggler, I discovered that df.exe is not working here. Here's the command line I've tried:

C:\systools\Defraggler\Df.exe c:\

Under Win XP, the CMD window quickly - a matter of two seconds, max - populated with "Defragmenting (0%)", up to 100%, and when I added the Shutdown switch, that worked, but as far as actual defrag, a check showed that nothing was done at all. Version is 1.18.0.185.

Same bug in my system (Win7 x64)

It worked using first df.exe /L and then df.exe C: