Export them in the file type that meets the requirements for your final use. Backing up the entire profile makes more sense if just doing it for a backup. https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data

My final use would be that for some reason unknown I lost all of my addresses. So would CSV be the correct media to main a copy?

No.

I'd either save the whole profile, or if you choose to simply safeguard your address books, all the *.mab files. Saving the whole profile includes your account settings, messages, filters, extensions, preferences and customisations.

https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data http://kb.mozillazine.org/Files_and_folders_in_the_profile_-_Thunderbird

CSV file and LDIF files have to be imported, creating new address books. They don't restore lost or damaged address books efficiently. CSV files can't preserve Mailing Lists. Until recently, when re-importing, you'd find that the field order is different when importing, so you'd have to go through an alignment/rearrangement procedure. On the other hand, the mab files preserve your address books "as-is" with no fiddly import or conversion.

Zenos said

No. I'd either save the whole profile, or if you choose to simply safeguard your address books, all the *.mab files. Saving the whole profile includes your account settings, messages, filters, extensions, preferences and customisations. https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data http://kb.mozillazine.org/Files_and_folders_in_the_profile_-_Thunderbird CSV file and LDIF files have to be imported, creating new address books. They don't restore lost or damaged address books efficiently. CSV files can't preserve Mailing Lists. Until recently, when re-importing, you'd find that the field order is different when importing, so you'd have to go through an alignment/rearrangement procedure. On the other hand, the mab files preserve your address books "as-is" with no fiddly import or conversion.

OK Thanks So I've copied/Pasted my Profile to an external drive, its about 2GB in size. One of the files in the Profile is :- abook.mab is that the Address Book? If so how would I recreate in T. Bird if I had a problem? I've looked at going into Tools/Import/Address Book but the .mab extension does not show

Just paste it into your profile using your file manager.

abook.mab = Personal Address Book history.mab = Collected Addresses abook-1.mab and similar with numeric suffixes are user-defined address books.

Totally lost me. For a start I have an address book named "Yahoo Contacts" this is the initial import to T.Bird I can't see this in the profile!, where is it? Also how do I "Just paste it"?

You copied your profile to an external device. So you know how to copy. You can copy all or parts of your profile back in the same way.

If my Thunderbird was broken, I'd restore the whole profile. I wouldn't try to cherry pick the specific parts. I don't think the address book is particularly more vulnerable to damage than any other part of the profile.

If your backup is up to date, what's wrong with just copying all the mab files? Then it doesn't matter which one represents which address book.

If you want to export/import just as a backup for Thunderbird, the LDIF file format would be more useful. But it isn't a backup. You can't restore from it; you'd import it creating a new address book.

The CSV format is best suited to exporting your data to a different program, just as you used it to import your old yahoo address book.

Zenos said

You copied your profile to an external device. So you know how to copy. You can copy all or parts of your profile back in the same way. If my Thunderbird was broken, I'd restore the whole profile. I wouldn't try to cherry pick the specific parts. I don't think the address book is particularly more vulnerable to damage than any other part of the profile. If your backup is up to date, what's wrong with just copying all the mab files? Then it doesn't matter which one represents which address book. If you want to export/import just as a backup for Thunderbird, the LDIF file format would be more useful. But it isn't a backup. You can't restore from it; you'd import it creating a new address book. The CSV format is best suited to exporting your data to a different program, just as you used it to import your old yahoo address book.

Zenos, Very good explanation/advise if I may say. But my concern is that within the Profile I've now copied there are 3 .Mab files. But I have 5 address books on T.Bird Imported from Yahoo Personnel Collected Plus 2 groups But are the "Groups" included within the contents of the Personnel Address book copy?

"Groups" (Mailing Lists?) are stored in mab files. LDIF files are also capable of preserving Mailng Lists. Unfortunately, CSV files are not.

If it's important to know which mab file does what, all I can suggest is to search them, using your operating system's search tools, for a distinguishing name or email address, then write yourself a summary text file, or store the mab files in named folders.

If you go to the config editor, type in

ldap_2.servers.*.filename

it will show you the address books and their corresponding file names.

Zenos said

"Groups" (Mailing Lists?) are stored in mab files. LDIF files are also capable of preserving Mailng Lists. Unfortunately, CSV files are not. If it's important to know which mab file does what, all I can suggest is to search them, using your operating system's search tools, for a distinguishing name or email address, then write yourself a summary text file, or store the mab files in named folders.

Thanks for all of the help. I don't want to delve where Dragons go! So I will just believe that the copy of profile has picked up everything. From now I will update on regular basis, hope I never have to use but glad I've got it Many thanks again