why do i get double copies of EMAIL in MAIL app?

i just renew my account in the MAIL app one week ago.

Today i open MAIL app, and the new maiil that i got from yesterday i have double copies?

what is wrong and how can i fix it?

also is there any better apps for mail that people use?

thank you

JediMeister said:

Only fixes I've seen for this are to rebuild or reindex Mail. And what do you mean when you say that you renewed your account in Mail?

Click to expand...

thanks iam tryin to rebuild right now

well a week ago, i want to know know how to delete emails in MAIL so they would also get deleted in my gmail web account.
so somebody told me to delete me old (POP) account in MAIL and to start a new one using (IMAP).

i try but it didn't work for because the emails were not updated right in my MAIL app and my gmail account.

does anybody know how to do this right?
or know where can i get directions to do right?

thanks
let me know