Failed to Delete / Move Organizational Unit in Active Directory

I think I rarely touch about Active Directory, so let's start with a basic one. Let say, one day you want to housekeep your OU structure, delete or maybe move some OUs to different locations, but you got an error :

You do not have sufficient privilages to delete <OUName>, or this onject is protected from accidental deletion.

or

Windows cannot move object <OUName> because:

Access is denied.

Well, if we look at the first error, it is clear cut, the object is protected from accidental deletion, so the object needs to stay there. Whereas for second error, it just mentioned "access is denied". 

Issues :

• Can't delete or move OU, either one of above errors prompted.

Troubleshooting 

1.  Right click at the target OU, and click at Properties
   
   
   
2.  Properties window opened. Click at Object tab
   
   
   
3.  The checkbox " Protect object from accidental deletion " is checked.
   

Resolution :

1.  Uncheck the " Protect object from accidental deletion " checkbox. Press Apply and OK
   
   
   
2.  You can now delete (or move) the OU.