There are a couple of solutions available to you. If you meet the requirements for this app listed in our marketplace this should help you send your contacts over to your Constant Contact account. If you do not meet those system requirements, then you can export in a VCard format and convert that to a CSV file. A converter can be found by a google search if needed.
If you need help with the file of contacts, we can also try to assist you in getting that into a format that can be uploaded into your account. You can email it to social_support(at)constantcontact(dot)com with the username, the file attached, and a reference to this post.
Once you have downloaded the plugin, authenticated to Constant Contact in Settings, select the Contact list you want the Apple Contacts to sync to in Constant Contact then you will just want to highlight your Groups, selecting one, some or all card(s) then press "Sync".
Since the plugin is running on your MAC and connected via the internet sync speeds can vary DRAMATICALLY so allow time (hours) if syncing more than a few 100 Contacts. Then just leave the app running while you do other tasks on your MAC as it will wrap up syncing once it is done.
Check your Constant Contact Lists afterward to see all the Apple Contacts you selected synced up.
Just note that because it runs on your MAC that everytime you open it or leave it idle for 10 minutes you will need to login via the app's Settings tab to get started as it needs to talk to Constant Contact to see your lists to sync Contacts to.
To see more around topics on Apple Contacts SyncApps see our community here...
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