Step 1: Open Start menu, right mouse click on Computer and from context menu choose Properties
Step 2: Control Panel window will open, form left side of the window click on System protection
Step 3: When small window open choose System Protection tab and then from Protection settings select your local drive and click on Configure button
Step 4: Under new window locate the section Disk space usage and scroll the slider down to lower percentage. Click OK to save your changes. If you restore point space is too low don’t worry because windows will delete older restore points and make more room for newest one
Step 5: Now of you really need/want to reduce the space used by Restore Point you can also turn it off completely (I would not recommend it). To do that repeat Step 1, Step 2 and Step 3
Step 6: Then select Turn off system protection and click OK to save changes.
Warning: If you decrease the disk space to be smaller than the space that is currently being used by system protection, older restore points, including previous versions of files, will be deleted.