Restoring all contacts from Time Machine
You have a backup - that's good, and it's got valid data which is even better.

First, I suggest taking a quick backup of your contacts as they stand right now.  It might not be required, but in case you mess up the restore, or even if you subsequently realise you now have recent updates missing, it's wise to have a safe copy.

Firstly, take a fresh Time Machine backup, and then we will make a local extra backup archive just of your contacts:

Contacts Menu &gt; File &gt; Export &gt; Export Contacts Archive - stick the backup file whateveryoucallit.abbu anywhere, like your desktop for now

Now you have multiple safe copies, you can go into Contacts, and just delete everyone.  All your groups, all your contacts.  You can get them all back from your export you just made.

To restore your contacts, you need to follow these steps:


1 Open Contacts
2 Enter Time Machine
3 Go back in time to find your good data


You've already got this far, now you need to actually perform the restore...  The remaining steps are:


4 Select what you want to restore, there are various ways to do this, one at a time (no thanks, or click on the top entry, then shift click on the bottom entry in a list to select the whole list etc.  Try it a group at a time perhaps, and then go back onto Contacts to show it has arrived.
5 Click the restore button