By default, the value is set to 15. This number can be changed through a registry tweak. Start registry editor (Start> Run> regedit). Browse to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer.
Here, right-click in the right pane and create a new 32-bit DWORD called MaxRecentDocs. Double-click on the entry and give it a Decimal type value of how many ever entries you want in the recently opened file list. Reboot when youâ€™re done and the changes will be applied.
If you do not want to have a list of recently opened files at all, the easier way is to right-click on the taskbar and click on Properties. Click on the Start Menu tab and uncheck the â€œStore and display a list of recently opened filesâ€ box.