How Windows 7 defrag schedule work

[DavidE]

What was the PC doing from 3AM to 9AM?
Was it turned off, sleeping, hibernating, turned on sitting at the Windows logon screen, ... ?
A scheduled task can be set to WAKE the PC, but I don't know if it can start up a PC that is turned off ...
If you have a laptop, power settings may affect the task ...

This is what I see as the default on a Desktop (no battery):

 

[Mang Nux]

What was the PC doing from 3AM to 9AM?
Was it turned off, sleeping, hibernating, turned on sitting at the Windows logon screen, ... ?

Sitting on the logon screen. It's a PC with continuous power.

 

[DavidE]

Interesting.
I don't use my PCs that way ... so I can't say what would happen.

I would Enable All Tasks History in Task Scheduler
Then you could see if and when the defrag task runs or tries to run, and what "errors" (if any) are logged ...

If the task doesn't run before 9AM, you may need to look in Event Viewer for more info about this ...