If you are looking for an easy way to
open EML file in Thunderbird then I would recommend you to use the
Advik EML Converter. The software can quickly import EML files into Thunderbird profile in a few simple clicks. It has a dual mode that enables you to open single or multiple EML files at once. The tool preserves all email attributes and structure during the process.
Steps to Open EML Files in Thunderbird
1. Run the tool and add .eml files.
2. Select the required EML files.
3. Choose Thunderbird as a saving option.
4. Click Convert button to begin the importing process.
Now, open Thunderbird and check imported files here.