I recently downloaded my Facebook data to see what they had. Even for me an experienced web head, I was surprised at the information they had, including contacts names and phone numbers of people not related to my contacts on Facebook.
So I realised Facebook had been secretly uploading contacts from my phone.
I investigated further and checked the “Continuous Contacts Upload” setting was turned off on both my Android and iPhone.
Facebook for Android:
1. Tap Menu icon.
2. Tap App Settings.
3. Tap Continuous Contacts Upload to turn this setting on or off.
iPhone or iPad:
1. Tap Menu icon.
2. Tap Settings > Account Settings > General.
3. Tap Upload contacts to turn this setting on or off.
Then I typed into facebook.com help “why are facebook uploading my contacts”.
At the bottom of the results I noticed it said “Turning off contact uploading in the Facebook app doesn't automatically turn off contact uploading or call and SMS (text messaging) uploading in the Messenger app.“
So I looked in the Messenger app and think that was the offending app that uploaded my contacts even though “contact uploading” was disabled…
In Facebook Messenger app > Click on your Profile image > People > Manage Contacts >
I also created two test contacts on my mobile to see if Facebook is still uploading my mobile contacts, so when I do a data download in the future I can search for those hidden numbers. If the new hidden numbers in my Facebook data download, the problem will not be fixed.
Reference links:
https://www.facebook.com/help/147699975301738
https://www.facebook.com/mobile/facebook/contacts/
https://www.facebook.com/help/messenger-app/1363969317082393
p.s. When the EU sue Facebook for privacy invasion again. I wish some of that money would go to the ordinary citizens affected.
