Method 1: (one per email compose)
The problem is the Outlook Express can’t see attachment in email which sent as “Rich Text Format” so the solution is when you compose an email that you will be sending to recipient that using Outlook Express you need to send it as “plain text” and the following are the steps:
. Before you attach the file, click “Format Text” tab, then click on line “Plain Text”, switch back “Message” tab and “Attach File”
. Continue with your email composition then send.
Method 2: (one time per email address)
. Open that specific contact by double clicking the item in your Contacts folder (Notes: if the contact is not already in your address books then add to your address book)
. Hover on the email address of the contact and a Address Card pop-up will become visible.
. On the right side of the contact card you’ll see a menu button. Click on it and from the list choose; Outlook Properties, Make sure that the “Internet format” is set to “Send Plain Text Only”.