Rated 5 out of 5 stars
Recently I started Thunderbird to see a message cannot write to disk, check there is enough space. When the mail summaries page was shown no data for correspondents, space usage graphs and Email patterns are shown, There is over 24GB free on the disk.
I have tried uninstalling and reinstalling Mail Summaries and have tried the development version all with the same result.
You could try checking the error console (Ctrl+J on Windows). Also, make sure none of your mail folders exceeds 4 GB (or maybe 2 GB on some platforms; I'm not clear on what the limit is these days).
Finally, if you have issues, please post reports on the support page (linked on the right side of the main page for this add-on) instead of here: https://bitbucket.org/squib/mail-summaries/issues?status=new&status=open