Can I attach files to an e-mail message?

Yes, you can attach up to 5 files to an e-mail message, as long as you subscribe to the Message+ feature.

However, attaching files to a message is generally not recommended for several reasons. Read on.


1) Sending speed. For a given bandwidth, a message with an attachment is sent more slowly, as well as being downloaded more slowly. That's because the overall message size is larger. The larger the attachments, the slower the message will be sent.

2) Inconvenience for recipients with limited connectivity. All users who have a slow internet connection may take minutes or even hours to download the message. Since this can cause a substantial inconvenience, unless the message is of great importance, users will unsubscribe in order to avoid having the same problem in the future, or even file a complaint against your company.

3) Mobile users. More and more users check their e-mail through mobile devices. Many smart phones now download a portion of a message, by default, to avoid the risk of attempting to download a large message on a slow connection. However, in some cases the phones will not even attempt to download the message (typically above 200KB), or try to download it and cause the email client to freeze.

4) Slow connections (e.g. 3G). Many users check their email with their laptop while traveling (e.g. on a train or at an airport). The connection is typically slow in many of those circumstances. In this context, the downloading of an email with a large attachment involves a significant slowdown, especially where wireless coverage is limited or there is a high concentration of users. A slow connection can create a serious issue when downloading large messages: most email clients (e.g. Outlook, Eudora, Apple Mail, Thunderbird, Lotus) cannot choose which messages to download. Messages are downloaded in the order in which they were sent: if one of them is too heavy, users may not be able to download any other message. This will likely lead to frustration, and probably unsubscription or activation of spam filters if the culprit is a message you sent.

5) Size of the mailbox. In many situations, especially relating to corporate mailboxes or old ISPs, there is a limit to the total mailbox size, which can be as small as 5 to 10 MB. This means that getting even a few emails with large attachments (greater than 500KB) can quickly fill up the mailbox, with the result of rejection of any additional messages. This will likely lead to frustration, and probably unsubscription or activation of spam filters if the culprit is a message you sent.

6) Deliverability issues. In several of these scenarios described above, if the recipient unsubscribes the result is a reduction in the number of subscribers. If the recipient sets a spam filter (safer in blocking delivery of additional email of the same type), you can create a domino effect for which the provider - or network administrator - may mark as spam all messages sent from you. This can obviously create serious deliverability issues. 

7) Temporary block by ISPs. There may be situations where the recipient's mail servers are overloaded because of high traffic, as well as spam. In these situations special measures are put into place to try to bring the situation back to normal. For example, a limit to the size of the message might be introduced to limit the overall amount of traffic. Such situations have occurred at times of particularly heavy traffic (e.g. Christmas season).

8) Best practice. Statistically, in 2008 only 0.4% of emails sent through our system were sent with an attachment.

For these reasons it is recommended that you send attachments only when you are sure that the recipients prefer to receive them as opposed to sending links to the same files.


a) You will avoid the issues described above.

b) You can then track activity on the link to the file (e.g. how many times the link was clicked on).

c) Control access to the file: each link is unique: if you see unusual activity on a certain link, then it means that the link might have ended in the wrong hands. You can then decide to remove the file.

d) A more efficient Internet. Only recipients interested in the file will download it. If, however, the file is attached to the message, all recipients will be forced to download it, generating a higher traffic and causing a less efficient use of the Internet.

e) In order to correct any errors "on the fly". If it turns out that the file is not the correct one, you can quickly replace it. If it has been sent, however, there is nothing you can do, other than resending it.


  • Log into your console and load the page to create/modify a message
  • Enter the text for the link (e.g. "Click here to download our latest report")
  • Highlight that text and then click on the "Document Manager" icon
  • Click on "Upload Document", then on "Browse" to upload the file from the PC
  • Click on "Insert": the system will turn the highlighted text into a link to the file that you just uploaded
  • Of course, you can also paste a link to a document hosted elsewhere (e.g. on your own Web site). Make sure to use the full URL to that document (copy and paste that URL in another browser window to ensure that it loads properly).
  • Users will be able to download the document by clicking on the link. It is recommended that you always include a text link and not just an image link in your message, as images are often not downloaded by default, and therefore users may not see the link.