As Didier says, if you have not installed SketchUp correctly all kinds of unexpected file & folder permission issues can appear...
To repeat what has been stated in many places before...
To fix your installation...
Login to Windows as your normal user-account [NOT the specialized administrator account - BUT if your normal user has some admin-powers that is OK]
Ensure SketchUp is closed.
Find the SketchUp installer's exe file - usually in your Downloads folder.
Select its icon, right-click > context-menu > "Run as administrator"
When prompted choose "Repair".
When it completes retry SketchUp and see if these kinds of issues are improved...