Message body does not display in emails
Thunderbird stopped displaying the message body in emails. When double clicking the email to open, the headings will appear but not the message body. If you View Source, the message is in the source, but just not displaying. On some emails, I can change the View Message Body as text and the body will appear, other messages is will not. I can't figure out a reason why some will and some will not. I tried repairing the Inbox folder but this did not help.
Opaite Mbohovái (1)
It sounds like your mail files are corrupted. First of all create a backup of your Thunderbird profile folder. https://support.mozilla.org/kb/profiles-tb#w_backing-up-a-profile
Try to move one of the troubled messages to a different local folder. You may want to create a new local folder for that.
Does the message show properly in the new folder?
Corruption is often caused by anti-virus software messing with Thunderbird mail files. It is therefore recommended to create an exception for the Thunderbird profile folder, so that the real-time scanner won't attempt to scan the profile with your mail.
For more information on the profile location see http://kb.mozillazine.org/Profile_folder_-_Thunderbird
Also see http://kb.mozillazine.org/Keep_it_working_-_Thunderbird