I have got many thousands of emails. From time to time my inbox gets full enough for a warning sign to come up - so I have a clean up by deleting and/or saving to a folder within "local folders" and I regularly clean out my deleted folders and recompact. However in the last few days I have been getting a warning tab come up saying "75% full" fairly randomly - in other words it seems to be independent of whatever folder is active at the time. Does Thunderbird have a maximum capacity including all local folders? There are many emails (including attachments, of course) which I do not want to delete whether for archive or for nostalgic reasons. If there is a maximum overall capacity is there any way of "exporting" folders of emails with their attachments to free up space for the program but leaving me able to invoke these emails should the need or occasion arise?