Over the last couple of days I have made a number of attempts to send an email with a song attached. The song is 4.5mb, well within the limit to attachment size of my ISP, but every attempt produces the following message:
The email app is Thunderbird, and I have no idea if the temporary directory is a Thunderbird or Windows directory, though I lean to the latter. I have checked and I have all the appropriate permissions on the security tab, and I am not sure why a temporary directory is involved in the attachment process.
Helpful suggestions welcome

Thunderbird does not have a size restriction. If your ISP allows that size, then the SMTP sever should too. So I wonder if the problem is not that single quote character in the song name.

Do understand that if that song is copyrighted, it is not legal to give it to someone else without the required compensation.

Hi Digerati
I assume you are referring to the "á"
Removing it removed the problem, seems a bit sad that Thunderbird stumbles over something like that, how does it cope with French or Spanish? Or a heap of other non English languages for that matter.
Copyright issue noted, I will behave myself.
Thanks.
Why do I have only the option of Quick Reply here? Can't use smilies

It looks like Oxala' in your screen shot. I am glad you got it sorted out.

As far as smilies, I don't know. Don't you see a Go Advanced button?