In TB 68, there's no straightforward way to import the non-default mab files. Help/Troubleshooting, click Open Folder to open the profile, close TB. Rename abook.mab to abook.mab.bak. Copy abook-1.mab into the profile, and rename it to abook.mab. Start TB, open Address Book. Personal Address Book (PAB) now represents abook-1.mab. Create a new address book, name it e.g. abook1. Drag the contacts from PAB and drop them onto the abook1 icon, i.e. move the contacts to abook1. Open the profile, close TB, delete abook.mab and copy abook-2.mab into the profile, renaming it to abook.mab. Restart TB, create a new address book named abook2, drag the contacts from PAB onto abook2. Keep doing this until all mab books have been imported into separate address books. At the end, close TB, open the profile, delete abook.mab, rename abook.mab.bak to abook.mab. When TB restarts, you will have the original PAB and the other mab files in separate address books. Contacts can be moved between books by drag and drop, or copied by holding Ctrl while dragging.

The easiest and quickest way I can think of is to use an add-on to load the other mab files into your current profile, then go to the address book manager and copy the contacts from the loaded books into the main one via drag and drop. After that, you can simply delete the loaded extra books.

Install the Addressbooks Synchronizer add-on then restart Tbird. If the menu bar is not visible, press the Alt key to make it visible then go to Tools > Add-on Options > Addressbooks Synchronizer. Alternatively, open the Thunderbird menu then go to Add-ons > Add-on Options > Addressbooks Synchronizer. In the Addressbooks Synchronizer dialog that opens, switch to the Import/Export tab then under the Load an addressbook section, click the Browse button and locate the mab file that you wish to load into your current profile then click the Load button. The mab file will now be accessible via the address book manager. Repeat the loading process for the other mab files then close the Addressbooks Synchronizer dialog when finished. Now you can access the loaded address books and drag their contents into the main address book. Use Ctrl + A to select all contacts in the selected address book then drag and drop them into the main address book.

Thanks for the replies (I've seen 2 as I prepare this reply).

I think I understand both solutions but maybe there is another way if I give a better explanation. I have five mab files in the Profiles subdirectory that contains most of the key files (about 75 to 80 in total). The 5 files (and their sizes) are all in this same folder identified as

abook.mab (426 KB) abook.1.mab (52 KB) abook-2.mab (42 KB) abook-3.mab (2 KB) abook-4.mab (17 KB)

If I understand correctly the Personal Address Book ALWAYS refers to the file named abook.mab

I believe there is some overlap among the various address books but also some unique addresses and, more importantly, created lists as the other 4 address books have different dates and were probably created for reasons I've forgotten although I've had some Thunderbird crashes and Operating System upgrades over the years.

Of the 2 solutions mentioned above, are either of them impacted by the fact that the 4 other address books (abook-1 through abook-4) are already in the same folder as the main abook.mab file?

And given that they are all in the same folder is Solution 1 better than Solution 2? Or is there a better way to get all 5 address books into one?

Thanks, again.

How many address books do you have in Address Book? The ones other than PAB may already be representing abook-1.mab, abook-2.mab etc., although it may not be obvious by comparing the mab name and the address book name. The method I proposed is a way to import mab files that may be from old profiles or ones that aren't linked to current address books. You can see which address book, besides PAB, is based on which mab file by editing the address book in TB and then checking the Date Modified of the mab files.

Personal Address Book is always abook.mab and any file named abook.mab will appear as PAB when TB is restarted. Copying any other mab file (except history.mab - Collected Addresses) into the profile folder will not result in it appearing in Address Book.

Of the 2 solutions mentioned above, are either of them impacted by the fact that the 4 other address books (abook-1 through abook-4) are already in the same folder as the main abook.mab file? And given that they are all in the same folder is Solution 1 better than Solution 2? Or is there a better way to get all 5 address books into one?

Since the address books are not loaded in your Tbird profile despite residing in the profile folder, I would move them elsewhere outside of their current location, then work with them from there, regardless of which method you choose to use. It's best to have their copies isolated for backup because there are no guarantees when it comes to data safety.

As for which solution is better, that will depend on you. My method doesn't involve renaming each of the books in turn to get Thunderbird to load them. I find that to be cumbersome. The add-on loads each of the mab files into the current profile and makes them accessible right away.

You'll definitely end up with duplicates once you've copied them all into the PAB. Unfortunately, you cannot relocate lists from one address book to another, but you can recreate them under the PAB, then drag and drop their contents from the other address books into them. Once you have the merged PAB, you can clean up duplicates whichever way you deem suitable.

I tried the first method as I was unable to locate the Addressbooks Synchronizer add-on and had success for the first 'old' address book.

I am guessing that ultimately after going through the process of individually renaming each abook-#.mab to a 'temporary' abook.mab, creating a new Address Book and dragging the PAB into that new Address Book and either deleting or renaming that 'final' abook.mab file (after closing TB each time after the drag/drop) I will rename the original file now named abook.mab.bak to become the new and final abook.mab that will now contain all the newly named Address Books added along the way in addition to all the addresses that were in that original abook.mab file that was named abook.mab.bak throughout the entire process. Does this appear correct?

If so I will mark this solution solved once I get the answer to other (hopefully) simple questions.

1 -- How do I create a backup of the final abook.mab file?

2 -- Since I know I will have multiple duplicate email addresses at the end of this process is there a tool to automatically delete exact duplicates from both the main address book and any created lists?

Thanks, again, for your assistance and your patience.

You first have to install the add-on from the Thunderbird add-ons repository. See https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

If so I will mark this solution solved once I get the answer to other (hopefully) simple questions. 1 -- How do I create a backup of the final abook.mab file? 2 -- Since I know I will have multiple duplicate email addresses at the end of this process is there a tool to automatically delete exact duplicates from both the main address book and any created lists? Thanks, again, for your assistance and your patience.

To backup abook.mab, just copy it to a safe location outside of the profile. To backup any other address book, export it as an LDIF file from Address Book.

Duplicate Contacts Manager.