Hello,
There is a service that is running in services.msc called Disk Defragmenter with a description "Provide Disk Defragment capabilities." If I look in msconfig under services, it's also listed in there with a check mark in the box.
Now if I look in the Event Viewer in Windows Log > Application and scroll through it, there are several events listed as Defrag (Screenshot attached). Now it doesn't appear that these are complete disk defrags; however, this laptop is a SSD and doing a disk defrag is pointless not to mention it can actually harm the hard drive.
Does anyone have any idea what this event is doing when it runs or boots? I've looked to see what the service actually does but can't find anything other than it allows defrag to run.