You have already selected:

Tools > Options > Compositions > 'Addressing' tab Under 'Address Autocompletion' if you are using Thunderbird 'Address Book' to store contacts and their email addresses. Select: Local Address Books' click on OK.

Click on 'Write' In a TO field, start to type the name or email address of person and you should get a drop down list of possible matches for you to select saving you from typing the whole thing manually and potentially making an error.

Also please check Account Settings.

Right click on mail account in Folder Pane and select 'SEttings'

click on 'Composition & Addressing' for the maila ccount Under 'Addressing: When looking up addresses: select: 'Use my global LDAP server preferences for this account.

below that 'Addressbooks for addresses autocomplete' click on 'Edit' button select any or all address book listed. click on OK

check these settings for all other accounts. click on OK

All that is exactly as I have it BUT it is not autocompleting - it offers me nothing. I have been using TB for years and currently it is looking after 11 different email accounts - so I have some experience

in your answer 1: it is as set up, but on entering an address nothing happens other than what I type. All Addresses has about 270 addresses

in your answer 2: again it is set up as you suggest EXCEPT that you say "below that 'Addressbooks for addresses autocomplete'" there is nothing like that on the settings, either for any account nor for global preferences I do not have that option (see image file)

FYI: MS Windows 10 professional 32bit on an HP Desktop TB 45.0

Bonnyjarrs

re :below that 'Addressbooks for addresses autocomplete', click on 'Edit' button, select any or all address book listed.

Many people use the addon extension 'MoreFunctionsforAddressBook' and this adds that 'Edit' option.

So I included it just in case you already had the addon.

As you are not using that addon then it would not be available. However, I'm wondering if you have another addon which is causing a conflict. Test this using Thunderbird Safe mode. In Thunderbird Help > Restart with addons disabled

check to see if autocomplete works by offering drop down potential matches. Report back on whether it works in Safe Mode.

If it works ok in Safe Mode: Restart Thunderbird and it should restart in normal mode. Tools or Menu icon > Add-ons disable each addon extension in turn to see which is causing the problem and report back on which addon was the culprit.

It worked fine in Safe mode The addon that caused the problem is "Faster Autocompletion of email addresses" which is now disabled so my problem is solved - thank-you very much indeed

(as a pointer to whoever wrote that addon; addresses were being typed from the begining in red instead of black - in other-words; it was not looking in any of my addressbooks becasue that now happens if I am entering an address which is new to me - it turns red as soon as I get to a 'not-in my addressbooks')

again, thanks,

bonnyjarrs