If defraggler happens to be working on my C drive (not unusual considering how slow defraggler is) when I plug in a USB flash drive, it immediately accesses and locks the USB drive against removal. Considering I never want defraggler to touch the flash drive, this is a real annoyance when I go to safely remove the flash drive. This happens even though the drive is on defraggler's EXCLUDE list.
Yes I can yank the flash drive without using the safe removal option or I can break the lock between defraggler and the drive using Unlocker, but eventually defraggler notices either of these methods and gets confused by them and the GUI stops responding.
My suggestion is that defraggler should not touch any drive IN ANY MANNER if it has not been invited by the user to touch that drive.