Okay, since I posted this question I've made progress. It turns out the errors are being displayed in Mac "Notifications" which you can configure in System Preferences > Notifications > Thunderbird. So I was able to configure the popup to stay open until I close it. But I still can't see the rest of the error message. When I click the partial text it brings the Thunderbird window to the foreground but I see no additional info. When I click the Notifications icon in the Mac menu bar I see the same partial text with no indication of where to find the rest. And unfortunately there is no copying of the text in that window, so I can't give an actual example here. My original question, FYI: Newbie here. I just installed Thunderbird and am trying to figure out how to get the complete text of error messages that are shown in a popup. The text in the popup ends with "..." but clicking on the popup does nothing. The Error Console window seems to a variety of completely different errors and warnings, nothing matches the text I see in the popup. Unfortunately I can't give an example of the text that is shown in the popup because the popup disappears pretty quickly. I'm looking for either an error log that shows what was displayed in the popup, or a way to configure that popup so I can see the whole message. Versions: Thunderbird 38.7.2, Mac OS X 10.11.2 Thanks.