My email inbox is automatically deleting emails

Hello Laura Sievert,

Thank you for using Apple Support Communities! I understand that emails forwarding from your Gmail account to Mail on your Mac have been deleted. Not all of your older emails appear on the Gmail account as well. I would be happy to help point you towards a resolution.

I would like to start by clarifying a few details with you:

1. Has the Gmail account been added as an email account on your Mac, or are emails forwarded to a different email address such as your iCloud Mail account?
2. Is your Gmail account and the account in Mail on your Mac set up as POP or IMAP?

As far as older messages missing on the Gmail account, you'll want to reach out to Google to determine why that's happening. If your emails are being forwarded to a different email address on your Mac, try turning automatic forwarding off and back on again:

Automatically forward Gmail messages to another account - Gmail Help

On the Mac itself, I suggest checking if there are any Mail rules set up that could be causing the emails to be moved to trash or another folder:

Use rules to manage emails you receive in Mail on Mac - Apple Support

If you're forwarding the emails to an iCloud Mail account, check your junk mail filtering settings as well:

Change Junk Mail preferences in Mail on Mac - Apple Support

Cheers!

I have a pretty old g-mail account and it still has messages from many years ago (2013 is the oldest). How old were your messages? Are you bumping up against the storage limit for gmail accounts -- think it's 15GB at the moment. You can see how much your using on gmail by looking at the bottom of your gmail.com browser window or look at the Settings "Accounts and Import" window at the bottom -- the Apple Mail.app program doesn't know about this sort of thing. You can purchase more space if you need to from Google - click on the "Accounts and Import" tab in the Settings and there is a link at the bottom (Settings is a gear-looking icon in the gmail.com window on your browser in the upper right corner). Do you have any custom filters that might be deleting old messages?

Good luck...

Twice following apple updates I have lost most of my emails except for the last month. I am with UK2 and they confirm the mail had been deleted. This is a serious apple problem. Apple helped me recover some mail but of course they now all need sorting into separate folders as they were before. Its a shame that Apple do have some big problems that don't occur on Microsoft.

Andrew Macara