If you are having this problem and you, like me, don't want M$ totally controlling your system, you have most likely changed the scheduled task for defragging to anything other than letting it run sometime in the future or you have disabled it.
Go into Task Scheduler and click the right pointing arrow next to Task Scheduler Library, then the one next to Microsoft, then the one next to Windows. Find Defrag, double-click on the task in the center pane, click the Triggers tab and change the task time to run sometime in the future (Because I run it manually I tried setting a past date but it didn't work). Or if you, like I, disabled it, right-click the task in the upper center pane and choose Enable.
WaaLaa!