Syncing contacts between a Mac and iCloud.

If I add a new contact to the Contacts App on my Mac, the new contact also shows up on iCloud (so everything seems to be connected correctly). BUT, I would say that perhaps 50% of the older contacts in the Contacts App on my Mac never find their way to iCloud.

The suggested solution (on line) is go to System Preferences, iCloud and un-click the Contacts App check box, wait a while and re-click the check box. That does not help. I have even rebooted between un-clicking the Contacts App check box and then re-clicking the Contacts App check box. That didn't work either.

There must be a better way of forcing contacts sync to occur between the Apple Contacts App and iCloud other that fruitlessly un-clicking and re-clicking check boxes (which is being ignored).

And manually downloading a hundred or so vCards and re-uploading them to the Contacts (after comparing one list of contacts against the other) is not an elegant solution (but that does force the re-loaded contacts to sync over to iCloud).