Many users may have used Google Takeout to extract their Google content when notified about being over quota. The following procedure is a proposed method to import email from a Google Takeout file.
- Extract your Google Takeout files to directory on your computer.
- Install Mozilla Thunderbird (https://www.thunderbird.net/en-US/)
- Add the destination Gmail account to your Mozilla Thunderbird installation.
- Drag and drop the eml files from the extracted Google Takeout file into your destination Inbox in Mozilla Thunderbird.
If done successfully the emails will be visible in your inbox.
Setting Up Your Existing Email Address:
Example after drag and drop:
Example Uploaded Eml: