You can try software like WholeClear Thunderbird to EML Converter to convert Thunderbird emails to an EML format. This is reliable software that safely converts data without risking losing any data or making changes to the original folder. It keeps the folder structure and email properties intact during or after the conversion. The process of conversion is also very simple, which allows beginners or professionals to convert data without any hassle, because it has a clean and simple user-friendly interface. You can check out the demo version of this software, which lets you convert limited files for free, and that way, you can get to know its features and functions.