Beta updates since Thunderbird 38.7 (40 through 44) have required reload of all email messages in all folders, which has taken a couple days, but the loading was dynamic and one could see the number of messages increase whenever one reloaded a tab and one could see the texts of the messages added. With 45 (non-beta), no messages texts are visible, but the entire index of messages is visible with all the subject names. If one tries to view a message in the preview window or click on a message, the message text area just says the word "LOADING...." There is no indication of progress in the loading. This never happened with beta 40 through 44. Tried cutting the size of the Inbox by removing all messages prior to January 1st 2016 and it made no difference. Reverting to version 38 to be able to see my messages. With version 38 completely reinstalled, my messages appear immediately on application launch. There is no need to reload the messages from the profile simply because a "new" version has been installed. The latest product, version 45, appears to be unusable.