After upgrading from a prior version 6 of Thunderbird to version 31 the top level folder for one account did not show a list of emails. The emails were there and when you clicked on the display it displayed the full email but the space in the list was all blank rows and there was no column headings of subject, dates or recipients as you would expect.

The fix is trivially simple – click the folder display options and reset to the default. You can now fine-tune what you want displayed.