MY SENT EMAIL REAPPEARS IN THE INBOX

I solved the problem. For some reason "Follow-up" was turned on for several messages. I still don't know why or how. It was easy to click on "Ignore Follow-up" (I think under Messages). This kept the email from moving from the Sent folder to the Inbox. Thanks again for your help.

I should have been clearer. It's the Apple email that came with the iMac. The email provider is Gmail, but I only see the Gmail app when I'm using the browser - Safari. I have checked the Apple email settings for the Gmail and iCloud accounts. I had changed nothing, yet my sent email began to appear in the Inbox. last week. I move it to the Sent folder, it will reappear in the inbox. The only setting I saw that might relate is CC and BCCC. I can't remove these so I tried changing from CC to BCCC. The sent email still finds its way back to the Inbox. To make this more confusing, this only happens with a few sent emails. Thanks again for your help.

No. The problem is weird. It only happens with some emails. I've tried to note if there is anything different about these emails, but I can't see anything. Thanks for trying to help. I should clarify that after I return the email to the Sent folder, the next time I open my Apple email on the iMac the email has migrated back to the Inbox.

Thanks for the suggestion. I did check Google Mail but I will go through it more carefully. I will also pay more attention to the sorts of emails where I have the problem. I'll return to this page to let you know what happens. Thanks again.