What are the e-mail file size limits on Zen's mail platform?

In general, it is recommended you do not send or receive e-mails larger than 1.5 Megabytes in size. For larger files alternative transfer methods should be used.
 
E-mail is transmitted using SMTP - which stands for 'Simple Mail Transfer Protocol', defined in rfc2821.  This was designed for the sending of text, so is unsuitable for sending large files.

To ensure the best performance of our mail system there are some limits set to the size of e-mail that can be sent out through mailhost.zen.co.uk.

For both incoming and outgoing e-mail the limit is set to attachments with a maximum size of approximately 80 Megabytes, depending on the type of encapsulation (base64, uuencode etc.) used by your e-mail software.