Anti-virus software is known to cause corruption of Thunderbird mail files. Create an exception in your anti-virus software for the Thunderbird profile folder, so that the anti-virus real-time scanner will not scan it. https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data#w_how-to-find-your-profile

I have 2 different emails the one in question and (customerservice@wiegandsportsusa.com) that are on Thunderbird. The other is fine and not having the problem but the wiegandservices one is so it is not related to the virus software. It is something else that is causing the issue.

Not only do I get blank emails my emails also get all mixed up. The information in one email will come up in a different email even though there is no connection or reason why it should. Also when I open some of them all I get is code. So it is a lot of different errors. I have to constantly repair the folder. If I only have a couple emails in the folder it isn't bad but once I start to get past 20 or so it is terrible. As previously mentioned it is only my services email and not my other one even though both are being opened and read in the same Thunderbird app at the same time. My understanding is it is a mapping error on the server.