I am running Thunderbird 38.2.0 on Mac OSX Yosemite 10.10.5. I have the option set that puts new "sent to" addresses into my collected address book. There are quite a few older addresses in this book and auto-fill works fine when I am addresses messages to those addresses. The problem is that new mail "sent to" addresses are only temporarily being put into collected addresses. My collected address book will not long-term save new addresses and I have to re-type newer contacts. I tested this two ways. I typed an address in a new message that wasn't previously in Collected Addresses. I then sent the mail and checked Collected Addresses. The new address appears in the data base. I then quit Thunderbird and restarted. I checked collected addresses and that new address is no longer in the directory. I also did a manual save into the collected addresses directory. It "auto-fills" my new message to that contact. However, when I quit the application, that new address no longer appears in collected addresses. Is there a reason I am not persistently saving new contacts? This is getting to be quite a pain as I need to go back and find the person's address in old email and then manually type it in or cut and paste it. Jim