Open Outlook
Select your Contacts folder
Change your VIEW to PHONE LIST
Right-click on your title bar (Gray bar)
Select FIELD CHOOSER
Change "Frequently-used Fields" to
   "All Contact Fields"
Scroll down to "Private"
Drag "Private" onto the title bar and drop it
   between one of the fields

Now you can just click the box to turn on the
check mark next to each contact.

--
Nikki Peterson [MVP - Outlook]

How do I mark all my contact as private without having to
do one at a time