In System Preferences < iCloud, cannot enable Contacts

While this is similar to other posts on this subject, their solutions didn't work.

Today, I noticed that my Contacts were no longer present on my MBP (Yosemite). When I looked in the System Preferences <iCloud, the Contacts box was no longer checked. When I attempted to select it, the Contacts box would not remain checked. All the other iCloud boxes are checked and functioning. When I check the Contacts box, sometimes I will see "Setting Up" immediately to the right of the box. But, that quickly goes away and the check that I just put in that box clearing itself, i.e. the box switches itself from checked to unchecked. No error messages. I have confirmed that all my contacts are still in iCloud. And, when edited, they are syncing properly across my iOS devices.

I have searched through many posts of similar nature and tried the following that worked for others:

1.) Via System Preferences <iCloud, signing out of iCloud, choosing delete from this Mac when prompted, then rebooting, then signing back in to iCloud via System Preferences.

2.) Deleting the AddressBook-v22.abcddb and helper files and rebooting

3.) Force quit the iCloud Helper via Activity Monitor and rebooting

4.) Via System Preferences <iCloud, signing out of iCloud, choosing delete from this Mac when prompted, Changing my iCloud password (via iCloud.com), then rebooting, then signing back in to iCloud on my MBP with the new password via System Preferences (i.e., same as #1, but changing my iCloud password before rebooting)

The result remains the same...the Contacts box will not remain checked. I am stumped.