How can I get rid of Unkown Contacts for good?

[clporritt]

Unkown Contacts

My Nexus 5 has about a hundred contacts that I don't even know... some are e-mails and some are links to websites and some are names and phone numbers to people I don't even know. On several different occasions, I spent 30 minutes deleting them all and as soon as I log back into my phone, they're all there again. WTF???????

 

[B. Diddy]

Re: Unkown Contacts

Are you seeing them in the Contacts app, or in the Phone/Dialer app? Do you have any other apps (like Twitter, Facebook, or LinkedIn) that are set up to sync contacts with the phone?