FAQ for Thunderbird contact sync with Google

Also see the FAQ for thunderbird contact sync.

What is synchronized?

Thunderbird’s “Personal Address Book” syncs with Google Contacts.

sync google contacts withOr you can sync Google Contacts with an addressbook named after your Google email address.

What isn’t synchronized?

Zindus doesn’t sync Thunderbird mailing lists. Lists and the contacts in them are ignored. This feature is on the roadmap.

Contact conversion

Thunderbird and Google don’t support exactly the same set of contact fields.

The Thunderbird fields that map to Google are:

  • Full Name
  • Primary Email address and Second Email address
  • Phone Numbers: Home, Work, Work Fax, Pager, Mobile
  • Home and Work URLs
  • Instant Messaging (AIM)
  • Organization and Title
  • Notes
  • Birthday

Postal addresses fields aren’t synced by default because of differences in field formats, but there is a workaround.

Where Google supports multiple values for a contact field, Zindus syncs the first of those with Thunderbird. So if a Google contact has two mobile phone numbers, only the first of those numbers is synced with Thunderbird.

Where a contact on one side of the sync has fields not supported by the other, Zindus tries to preserve the unsupported fields during an update by merging the updated contact into the overwritten contact.

Thunderbird and Google Addressbook differences

No empty contacts

Without ever noticing it, you may find that you have contacts in your Thunderbird address book that don’t have an email address but do have data in some of the other fields, such as FirstName or LastName. If none of the Thunderbird contact fields map to Google contact fields, then as far as Google is concerned, it’s an empty contact, which Google doesn’t allow.

Thunderbird contacts of this sort can’t be synced. Your options are:

  • edit the contact to add a Display Name or email address (even a fake one would be ok)
  • move the contact into a different Addressbook so that it isn’t synced with Google

It’s also possible for a Google contact with no email address or Display Name to map to a completely empty Thunderbird contact.  Contacts of this sort aren’t synced with Thunderbird.  If you want such contacts to sync, give them an email address or Display Name.

When rules break

The Thunderbird address book that is synced with Google must comply with Google’s rules.  If it doesn’t, the addon will help you fix it, see:

The Google Thunderbird address book: staying in sync

Error Messages

Unauthorized - Token Invalid

The first time the addon authenticates with Google, Google gives the addon an authorization token that the addon sends with subsequent contact requests.

The addon uses this token for months or even years until one day, the token becomes invalid - either because you changed your Google password, or because Google made it invalid (for a reason known only to them).

When that happens, you’ll see an error message:


In addon versions 0.8.15 and higher, simply sync again.  The addon will send your username and password to Google to obtain a new token. Versions 0.8.14 and prior, visit Tools/zindus, Edit the account and select “Test Connection”. This forces the addon to obtain a new authorization token.