How Windows 7 defrag schedule work

LMiller7 said:

The task scheduler provides control over what happens when the computer comes out of the idle state while a task is running. Open the properties for the task and select the "conditions" tab.

Note the second checkbox labeled "Stop if the computer ceases to be idle". Quite clear.
Note the third checkbox labeled "Restart if the idle state resumkes". Also quite clear.

Or have I misunderstood the question?

I did not saw thos options, it is quite clear indeed. The only case where a disk is not defragmented is when a user always close his computer as soon as he don't use it anymore. Thanks for clearing this up. Always good to let his computer idle at least one day per week.

EDIT: I looked at it in task scheduler, and the logged on/off section was greyed out (although there was a check on the "run whether user is logged on or not" box). Why is it greyed out?

That section will be disabled unless you select a user account other than the default of "SYSTEM". The SYSTEM account is always logged on while Windows is running so the the question is meaningless. It is common practice for programs to disable options that have no relevance in the current context.

pominator said:

I was playing around with the default Windows 7 defrag schedule and still can't figure how it work exactly.

The default schedule is set to start at 1h am wednesday with 3 minutes idle condition. Their is also a settings that set the defrag to start as soon as it can if a schedule is missed. If my understanding is right, if the computer is close in the night of wednesday to thursday, it will start to defrag next time it will be open and idle for 3 minutes. But what happen if you open your computer on friday, do some work and let it idle 3 mins. The defrag start but then you start back using your computer before the end of the defrag. Do the defrag stop completly and the next scheduled start is next wednesday ? Do it only put itself in pause until you idle again ? Do it put iself in pause until you idle again or stop automatically if too many changes are made to the filesystem ?

Anyway thanks if you have any info regarding this.

Edit : You can see the details of the schedule like this : Use Task Scheduler To Tweak Automatic Disk Defragmentation In Windows 7/Vista

I was curious about this so I looked at my History for this task.
On 2/28/2014 I see a defrag started, stopped for "not idle", started later, ...
Eventually it re-started and completed :)

In Task Scheduler I now use "Enable All Tasks History" all the time, on all my systems.
From what I found it does not impact system performance or disk usage in any noticeable way.
The W7 default setting is to have History disabled, for whatever reason ...
Enabling History allows looking back if I ever want to...

I don't normally turn off my PCs.
I use Hybrid Sleep, usually sleep is set at 30 minutes ...

I've noticed sometimes it doesn't sleep "at the expected scheduled time" ...
I found some programs prevent Auto Sleep while they are running.
Maybe defrag is one of these programs?

You could at least turn on "Enable History" temporarily to see what it shows for your scenario/question.
If you don't want it on all the time, turn it off after your testing.

LMiller7 said:

EDIT: I looked at it in task scheduler, and the logged on/off section was greyed out (although there was a check on the "run whether user is logged on or not" box). Why is it greyed out?

That section will be disabled unless you select a user account other than the default of "SYSTEM". The SYSTEM account is always logged on while Windows is running so the the question is meaningless. It is common practice.

OK. But if it's being run by 'system', and 'system' is always logged on, then why did it delay my sceduled 3am defrag until a 9am when a user was logged on?