Thunderbird was working fine (have been using as my main email reader for many years). Rebooted PC and when it came back Thunderbird config was gone (when I open Thuderbird it had no email or calendar and asks to configure a new email as if freshly installed). Thunderbird is set to auto-update, so no idea if this was broken by an update or some other type of config corruption. It appeared to update to 52.3.0 after the problem (when I checked the version page within help), not sure if it did anything before the problem. Is there a log file somewhere?