If Address Book doesn't retain additions or deletions, you can rebuild it:

https://support.mozilla.org/en-US/questions/996474

I got as far as, "Select Help/Troubleshooting Information, click Show Folder to open the profile folder, exit TB, delete or rename abook.mab" but I didn't see Show Folder, so I couldn't click on it. Also, The heading at the top of the suggested url says, "When adding or deleting addresses to the email address book information is not retained once PC is switched off and on." That is not my problem. For most entries I click on the line then click delete. And the item goes away. But for some I click delete and nothing happens right then.

For Macs, click Show in Finder to open the profile folder. The rest of the instructions apply to all systems. If you try to delete contacts and nothing happens, this is still the sign of a corrupted address book.

Delete function seems inoperable. highlight delete nothing - entry still there. Help?

keviquin said

Delete function seems inoperable. highlight delete nothing - entry still there. Help?

Did you try the rebuild process mentioned above?

I started to rebuild but 1) the reason stated in the link, "When adding or deleting addresses to the email address book information is not retained once PC is switched off and on" does not correspond to my problem. I can successfully delete some entries, but it seems that those without email addresses in the Mac OS X Address book, just blink when I hit delete and remain. Not only that but those entries do indeed have email addresses as I can input their names in the To line and their email addresses come up. 2) I got as far as "name the LDIF file" since I don't know what LDIF means. Also, I don't understand why I should select the Personal Address book as I don't have any entries in that one. The entries onlly show up in the Mac OS X Address Book. Regarding keviquin's suggestion, I don't understand "highlight delete nothing." Besides that "Delete function seems inoperable" is not my problem; the Delete function works on most of the entries, just not on those that oddly don't show an email address in the Address Book. BTW I tried adding the address but couldn't.

So, I will be happy to rebuild, but please tell me which Address Book and what's LDIF?

If the problem is only with the OS X Address Book, then you will have to search Apple support for ideas on how to fix it. The instructions for rebuilding address books apply only to the ones built into TB, even though TB can read the OS X book. LDIF is one of the formats that can be selected (Save as type) when exporting or importing address books, besides comma separated (.csv), vCard (.vcf) etc.

ngatu said

I started to rebuild but 1) the reason stated in the link, "When adding or deleting addresses to the email address book information is not retained once PC is switched off and on" does not correspond to my problem. I can successfully delete some entries, but it seems that those without email addresses in the Mac OS X Address book, just blink when I hit delete and remain. Not only that but those entries do indeed have email addresses as I can input their names in the To line and their email addresses come up. 2) I got as far as "name the LDIF file" since I don't know what LDIF means. Also, I don't understand why I should select the Personal Address book as I don't have any entries in that one. The entries onlly show up in the Mac OS X Address Book. Regarding keviquin's suggestion, I don't understand "highlight delete nothing." Besides that "Delete function seems inoperable" is not my problem; the Delete function works on most of the entries, just not on those that oddly don't show an email address in the Address Book. BTW I tried adding the address but couldn't. So, I will be happy to rebuild, but please tell me which Address Book and what's LDIF?

"Highlight, delete - nothing". My entries don't even 'blink'. they just stay there.

I tried the recommended LDIF fix. But that involves an LDIF file editor - that doesn't seem to be easily found.

I wonder if using a different format (comma separated?) and editing entries say, with notepad, would work to 'rebuild' an address book file?

I'm starting to remember why I stopped using T'bird years ago.

I suppose it doesn't really matter. I was just trying to tidy up the list. Thanks, all, for the suggestions.

I was under the impression that the MAC address book was viewable in Thunderbird but you could not delete anything via Thunderbird.

You have to open the MAC address book as normal - not in Thunderbird, then edit it.

I opened up Contacts and edited one of the problem entries -- it didn't have an email address. I added the address and then it appeared in TB's address book as an additional entry, now showing complete twice. Then I deleted one of them successfully. It's cumbersome, but it does work. Thanks for the hint Toad-Hall.

Same problem--unable to delete unwanted T'bird address book entries. How do I get to the MAC address book? I can't find it in MacMail or anywhere else.

When you click on the Address Book in Tbird a window opens that gives Mac OS X Address Book as one of the options. Or do you mean the Mac OS address book? It's name currently is Contacts, an app listed in Applications. Why was it changed from the obvious Address book? Dunno. It's one of the mysteries of life. Note my solution, just above, to delete a file was accomplished through Contacts.