By default Windows keeps track of which files you have opened with a particular program in its Jump List. Here’s how to limit the amount of entries it stores or even disable it altogether.
Stopping Windows From Populating Jump Lists
Right click on the taskbar and select Properties from the context menu.
When the Taskbar Properties dialog opens, switch over to the Jump Lists tab.
Here you can easily change how many entries are saved in each Jump List.
Alternatively you can disable it altogether by unchecking the last checkbox.
That’s all there is to it.