Shutdown after Defrag doesn't work

Defraggler Defraggler Bug Reporting
1

Defraggler version: 2.03.282

OS: Windows XP SP3

I check "Settings -> Shutdown after Defrag" and start to defrag my drive.

Defraggler won't shutdown if I lock my PC (By pressing Win + L).

Please help to fix this bug. Thanks.

2

Nothing can shut down a locked p.c. (except in a domain where a administrator sends a ps cmd)