The challenge you face is that the address book for each user (each machine?) is stored as a separate file within each user's profile (each installation of Thunderbird). So you have three files and you want to keep them all 'in sync', with only one person authorised to make changes. There's an article about it here http://kb.mozillazine.org/Sharing_address_books which I don't fully understand, it's quite technical in places. But I gather there are three main options: - One is to keep copying the files from one machine to the others. This is time-consuming and fiddly, but in principle straightforward. The article recommends an add-on that might help. - Another is to have a 'master copy' of the file on a shared drive which the three users access from their machines. The article appears to say that this used to be possible in earlier versions of Thunderbird and can now be achieved only with some technical stuff that I can't follow. - Finally there is the option to keep your 'master' in Google Contacts. There is an add-on for Thunderbird which synchronises its local address book files with Google Contacts, so if one person maintains the records via Google and you all synchronise your Thunderbird address books with Google regularly, that should achieve what you want. You will need to look into all three options further but I hope this is a helpful start to your quest.

Thank you Manchester Man - I'll certainly look into all the options - I think Google contacts could be the road to go down. Although we're all connected via office 365, so maybe this could be where the 'master copy' is held - it's all a bit goobly goop - is there a company that can set it up for us?? haha. Thanks for your time.

http://thunderbirdtweaks.blogspot.com.au/2014/10/sync-hotmailoutlookcom-contacts-with.html

I suggest you sync with the online address book. But as your using office 365 this might be better than Google for your needs.

However if your subscription includes an ldap address book, use that.

Thanks Matt - I'll ask the Administrator that set the office 365 account up - if she has, does that mean that her machine is the master and the updates to the address book have to be done by her?

I am guessing. I refuse to pay a Microsoft Tax. So I have no idea what is or is not included in an office 365 subscription and what is not.

The information I linked you to is for an add-on that will synchronize address books to outlook.com, as long as you all use the same user credentials to access the address book. In effect it acts as the server to update it's "clients"

Seriously you need the assistance of a local computer technician, not an internet help forum. Small business regularly uses these types of forums in an effort to save money. But the reality is IT is at the heart of modern business. It is not something you can afford to "wing". Like the Ghost busters. When it breaks, "Who you gonna call" Even in my day job working on a farm. We waste more time on defective IT product (auto Steer and GPS) than we do with other types of equipment breakdowns.

Excellent - many thanks Matt. My thoughts exactly. We've got a guy at the moment rebuilding our website, so I'm gonna call him!! You've been a great help - thank you :-)

We use ldap at my place of work to share the official company address book. It is maintained by someone with admin rights, and is read-only to mere mortals such as myself.