How to Open .mbox file in Gmail with Attachments?

How to Open .mbox file in Gmail with Attachments?

Gmail offer users to backup INBOX folder in .mbox file format via Google Takeout Feature. Howver there is no such option to Restore Gmail MBOX.
Thus I would like to suggest you to choose an alternate approach i.e. MBOX to Gmail Wizard. This utility will open .mbox file in Gmail with attachments. 

Steps to open MBOX file in Gmail are;
  1. Run MBOX to Gmail Wizard
  2. Click Add File and add .mbox file.
  3. Enter your Gmail login credentials.
  4. Click Convert button.
Finished! This is how you can open MBOX file in Gmail.