I have the same issue with Defraggler since version 2.16 (program hangs for many seconds with each mouse click in GUI, after which it seems to revalidate drives)...
PC Model: DELL Inspiron 1720
OS: Windows Vista 32-bit SP2
HDD: Samsung SSD 840 EVO 256GB
Debug log from running latest Defraggler (2.19.982) in attachments, suspicious entries listed below:
...
[2015-04-17] [15:46:50.565] 007a4 1 CVolumeManagerBase::UpdateVolume#340 Start update for volume \\?\VOLUME{xyz}.
[2015-04-17] [15:47:00.034] 01604 1 SsdOptimizer::TriggerTrim#185 Entering SsdOptimizer::TriggerTrim
...
[2015-04-17] [15:49:20.237] 01604 1 SsdOptimizer::ValidateVolume#140 Entering SsdOptimizer::ValidateVolume
[2015-04-17] [15:49:40.147] 01604 1 SsdOptimizer::TriggerTrim#185 Entering SsdOptimizer::TriggerTrim
[2015-04-17] [15:49:40.254] 01604 1 SsdOptimizer::TriggerTrim#185 Leaving SsdOptimizer::TriggerTrim
[2015-04-17] [15:49:40.254] 01604 1 SsdOptimizer::ValidateVolume#140 Leaving SsdOptimizer::ValidateVolume
[2015-04-17] [15:49:54.547] 01604 1 CMainFrame::OnDestroy#965 Entering CMainFrame::OnDestroy
...
P.S. In my opinion the easiest fix would be disabling 'SSD Optimizer' on everything lower than Win 7 (missing SSD Trim support)Defraggler.exe.2_19_982debug2015-04-17_15-46.txt