I am using Thunderbird V78.5.1 (32bit) on a W10 machine. Previously it worked fine. After the latest download it has become difficult to address a new or forwarded email. The only way that I can make it work is to copy and paste the email address in the "to" window. It will not automatically select an address of any sort. I use Cardbook but that should not make any difference. I did download a fresh copy of Thunderbird but that did not make any difference. With previous versions I could type a few letters of the selected address and Thunderbird would give me a few selected addresses to choose from. This version will not do that. Is there something that can be done? Thanks for your help. Rex Perry