If you are looking for a solution to open EML files in Exchange Online I would recommend you to use Advik EML Converter. The software can import EML files to Exchange Online in a few simple clicks. It preserves all email attributes during the process. It supports all latest and old versions of windows operating systems.
1. Run Advik EM1. Run this tool on your system.
2. Add EML Files 2. Add .eml files and click Next.
3. Choose Excha3. Choose Exchange Server as a saving option.
4. Enter your Exc4. Enter your Exchange Online account login details and click Next.
The software will The software will start importing EML files to Exchange Online. once the process is complete, you can open them.