some of my emails show a " this email has no content"

Hi there Mtruj789,

If there isn't any content in your emails on your Mac, it could be an issue with that specific email account. Try the steps below to see if they resolve the issue for you, including contacting your email service provider:

* Check whether Mail is retrieving a large message or a message with large attachments. See View Mail activity.

* Check if you’re using filters in the message list that are preventing expected messages from being shown.

* Try sorting messages in the message list by Date or another attribute, or searching for messages, to verify if you received them.

* Check whether your account is offline or disabled (inactive).

* If you’re missing emails from a specific person or group, check whether you blocked messages from them.

* Try quitting Mail, then opening it again.

* Choose Window > Connection Doctor, then follow any instructions in the Details column. Check for problems logging in to email accounts or with the incoming Mail server, or with firewall software blocking network traffic.

* Check whether you’re affected by another firewall, such as software installed separately from macOS or built into an internet sharing router, or administered by your email account provider. Contact the appropriate person for information.

* If you’re still having problems, contact your email account provider to verify your user name, password, incoming mail server, and other required information. Then verify the information is entered correctly in Mail account settings.

You'll find these steps here: If you can’t receive emails in Mail on Mac - Apple Support

Take care.

Try click "Mailbox" and at the bottom of the list is "Rebuild" - it worked for me.

I tried the rebuild action on Mail. It worked for a few days. Then some (not all) emails are back to no content.

Only fix I could find, I'm back to using Thunderbird. It's an excellent email program and no problems. Content always shows.