Macmail old contacts

Hey there Booberoi,

It's possible that the old suggested contacts are coming from Dropbox itself. This article explains how to delete suggestions.

How to add, delete, and import suggested contacts for sharing

Regards.

Hi Booberoi,

Thanks for contacting Apple Support Communities!

We understand that you'd like to delete certain contacts from your Mac.

Your Contacts can be associated with iCloud or your third-party email accounts that you have installed on your Mac so you may need to sign into that email account to remove your contacts. This article explains this process in detail: Delete contacts in Contacts on Mac - Apple Support

"You can’t delete contacts in read-only accounts such as Google and Yahoo; you must delete the contacts directly in Google or Yahoo, for example. 

If you don’t want to see contacts from a specific account, stop using the account in Contacts. To do so, choose Contacts > Accounts, select the account, then deselect its Contacts checkbox. If you want to see the contacts again, select the checkbox again."

We hope this helps.

Take care!