10MB Limit?

If you are sending this message with large attachment with a .Mac account, .Mac has a 10MB overall message size limit for received and sent messages and most ISPs and email account providers have similar or some limit on the size of received and sent messages.

Even if you can send a message that is about 15MB in size with your email account, the recipient's incoming mail server may have a smaller message size limit for received messages and the message will be rejected.

The email account provided by my ISP has a 10MB incoming mail server storage limit total for all received messages so even if my incoming mail server storage is completely empty and someone can send a message with attachment that totals 15MB in size, the message would be rejected by the incoming mail server for my ISP's email account since the size of the message is over my incoming mail server storage limit.

In addition in case you are not aware, all attachments must be encoded before being sent. The Mail.app uses MIME 1.0 for attachment encoding which is the internet standard. The encoding process increases the size of the pre-encoded file by 50% of so. A pre-encoded file that is 5MB in size will be roughly 7.5MB in size after the encoding process.

As I previously provided, most if not all ISPs and email account providers have a limit on the overall message size for received and sent messages.

Right now, Gmail isn't looking so bad.

Better look again since Gmail has the same 10MB message size limit for received and sent messages.

http://mail.google.com/support/bin/answer.py?answer=6589&topic=40

Hotmail's pay one (30$ a year) can handle 20 in and out, but the reciever may not be able to handle it.