Had a topic on this before but I think it got wiped
Selecting a boot time defrag option in defraggler "write an event to the system log" get's unchecked, and "write debugging information" changes to (none) in the Startup and Recovery Options.
The settings will remain if I go in and change them back to default after choosing a boot time option.
(these are the default settings before boot time defrag is selected)
Happening on Win7 64bit and Win8/8.1 64bit
defraggler version 2.17.898, althought it has been happening for many versions