MSG file formats cannot be opened directly using Thunderbird since MSG is a Microsoft Outlook message format while Thunderbird uses mainly EML file formats; hence, all that needs to be done is to convert MSG to EML.
For a free method, try this:
- Open the MSG file in Outlook, if available on any system.
- Save the message as an EML file.
- Open Thunderbird.
- Drag and drop the EML file into a Thunderbird folder.
This works fine for a few emails. But without Outlook, or if there are many MSG files, it becomes slow and messy.
A better approach would be to first change MSG files to EML and then drag and drop these EML files into Thunderbird. I have done such a process before when I had received folders consisting of multiple MSG files from some users who did not have an installation of MS Outlook.
WholeClear MSG to EML Converter is also one option to try when there are many MSG files. It can save MSG emails into EML format with attachments and basic email details like To, CC, and BCC. For small data, manual saving is fine but for bulk MSG files, a tool can save time.
My tip: test with 2 or 3 MSG files first, check attachments in Thunderbird, and then convert the full folder.
