That is unusual. The addressbook file name is abook.sqlite. Possibly it is corrupted? The 128 upgrade is not being announced yet, as there are possibly small bugs that will be trapped in initial days. You would have had to do this manually unless you use a separate app to handle software updates. you can verify presence of the file by clicking help>troubleshootinginformation, scroll down to 'profile folder' and click 'open folder' and then see if the abook.sqlite file is present. If it is not being recognized, my thought would be to exit thunderbird, copy the abook.sqlite somewhere else, and the start TB, click the tools>import >import from a file, and select the file to attempt a recovery..