Mail appears to be send - but isn't

Hello Anita.

Is this with a .Mac account or other account?

If this email account is provided by your ISP or by your web domain hosting company, you need to contact the email account provider for this account.

If someone sends you a message and you don't receive it with the Mail.app, have you checked the account via webmail access (if available) using a browser to confirm if the missing message is available on the server but not downloaded by Mail?

If not available on the server either, this is not a Mail.app problem.

If a message cannot be successfully sent by the Mail.app for whatever reason, it will remain in the Outbox mailbox. A message moved to the account's Sent mailbox indicates the message was sent.

Open one of these sent messages not received by the recipient. At the menu bar, go to View > Message and select Long Headers.

If there is text - including a mix of numbers and letters next to Message ID, this is additional proof the message was sent. When contacting your ISP or email account provider for your email account, you need to provide them the Message ID for any sent message reported as not being received by the recipient. Your ISP or email account provider for your email account should be able to trace the message with the Message ID for the message to determine if it was delivered to the recipient's incoming mail server.

This doesn't sound like a Mail.app problem to me.

What Allan said, except for incoming messages, if you cannot see them on the web, that does not necessarily mean this is not a Mail issue. That would depend on the type of account (POP, IMAP) and your Preferences > Accounts > Advanced > Remove copy from server settings if POP. It could be a rules issue, for example. The sending problems, however, also make me believe that Mail has no bearing on this.

Use Entourage instead, Apple Mail's got some serious problems with sending mail. Don't know what it is. Entourage delivers mail immediately, for instance.

Entourage delivers mail immediately, for instance.

There have been reported problems with receiving and sending with a .Mac account regardless the email client used or via webmail access but the email client does not determine how fast a message is delivered/received by the recipient. This depends on the SMTP server used by an account and the recipient's incoming mail server and since a sent message does not take a straight line from the SMTP server used to the recipient's incoming mail server, delays can also occur at various stops or transfers along the way.

All things being equal - sending the same message (at the same time) with the same email account and SMTP server using identical settings along with the same ISP, etc., there should be no difference with the email client used in ragards to the time it takes for the recipient's incoming mail server to receive the message.