Hello

If you are so afraid to losing data, you should take the habit of backing up your data. When you have several backups safely stored away on a regular basis, you will be able to do experiments without risking heart attacks.

As of the address book, my advice is to switch to the Cardbook addon. I have never found distribution lists (I assume that is what you are calling 'sublist') very usable in Thunderbird. Currently I don't even know how to actually *add* one (it don't matter much to me since my existing address book is a left over as I use Cardbook, however in my old address book I have distribution list and I wonder how I managed to create them !).

It's true that when your address book will be copied to the Cardbook, distribution lists will not be copied, but the advantage is that after about everything will be easier.

For a sublist, you should be able to highlight it, click the three dot ... just to the right, on the menu that appears click 'edit' and the list should open with an empty cell to add another email id.

re :How can I add a new address to a sublist without apparently losing all the addresses already in it?

If you want to create a new contact and then have that contact appear in a 'Mailing List'.

First add the contact to the address book that has the mailing list as a sub-list.

If the person contacted you via email then one method to get person in address book is to do this:

• select that email so you can see the 'From' email address in the headers.
• Right click on the 'From Email address' and select 'Add to Address Book'.
• By default it gets added to the 'Personal Address Book'

Once you have contact added to address book: In left pane make sure the Address Book containng the contact is expanded to show the Mailing Lists. Select that new contact in the list - left click and hold down to grab contact in the address book list and drag over to the left pane hover over the Mailing List and then release the left click to drop contact into Mailing List.

David's solution worked - which means the instruction was clear enough for me to understand it - but I had to go through Properties to find Edit. I'm 86; I didn't grow up with technology, and heart attacks are a very real possibility! Thank you for your time and your consideration. Jan

I'm glad all is okay.