How can I set the priority of an message?

There is no single, universally adopted, standard mechanism for specifying the priority of a message. There are, however, two MIME header fields; X-Priority and X-MSMail-Priority which together are recognised by the majority of desktop email clients.

X-Priority
The X-Priority field is a MIME extension field commonly used by non-Microsoft systems to specify the priority of a message.

The recommended values for this field are:

1 (Highest)
    2 (High)
    3 (Normal)
    4 (Low)
    5 (Lowest)

    3 (Normal) is default if the field is omitted.

X-MSMail-Priority
The X-MSMail-Priority field is a Microsoft defined field used to specify the priority of a message.

The recommended values for this field are:

    High
    Normal
    Low

In order to have the priority of the mail recognised by a wide range of email clients we recommend that you set values for both of the fields, for example:

MyMsg.Header("X-Priority")="1 (Highest)"
MyMsg.Header("X-MSMail-Priority") = "High"