I'm running Thunderbird 78.9.1 (64-bit) on Mac Osx. I have these add ons: * Provider for CalDAV & CardDAV * Send Later * Send Later Button * TbSync The problem I'm experiencing is autocomplete doesn't work when composing an email. I've checked the address book and it is empty - so records presumably are not being populated. I manually added a record to the address book and auto complete for that record still doesn't work. In Preferences - Addressing, Local Address Books is ticked. Also ticked is 'automatically add outgoing.... to Collected addresses' I've checked my profile folder, I tried deleting all files starting with abook.. hasn't helped Lastly I don't have a file called "abook.mab" instead it is "abook.mab.bak" Any help and pointers would be really appreciated.