Thank you for your quick responce. I appricate that.
I tried what you sugested and used 7z to compress the 7.5 MB file. That worked well and dropped the file size to 5MB. When I tried to mail it again, it still would not go through.
Have you heard anything about Yahoo limiting file size as a way of reducing spam, something called greylining?
I turned off my virus scanning temporarly to see if that would help, but even that did not.
I believe you are asking about grey listing The issue that you are experiencing should not be related to grey listing. Gray listing is when a mail server is configured to 4xx defer the first connection from a mail server that has not connected to it before. This is considered to be an "anti spam" measure by some people since a legitimate mail server will try to resend email again later and an incorrectly configured mail server and some spam programs will not bother to try sending the message again.
Can you copy and paste the exact and entire error message into this thread? I'd like to see exactly where and when the problem is occurring. Is it possible that Yahoo is allowing you to send the email, but that the person you are sending it to is not able to accept emails that big?