If you're trying to import MSG files into Thunderbird manually, you can drag and drop them or use the ImportExportTools NG add-on—but be warned, it’s not always reliable. Some emails might lose formatting, attachments could break, or the import might just fail randomly. For a smoother experience, I’d recommend DRS Softech MSG Converter Tool—it converts MSG files flawlessly, preserving all formatting, attachments, and metadata. Plus, it handles bulk conversions, supports multiple output formats (like EML, PST), and keeps your folder structure intact. Saves a ton of time compared to manual workarounds!

For more: https://www.drssoftech.com/msg-converter/