This blog post discusses two mistakes frequently made by users of Microsoft Outlook.The general problem is that some users of Microsoft Outlook wrongly assume that everyone in the world uses Microsoft Outlook. This general problem leads to many sub-problems, two of which I will discuss here.
Sending unreadable “winmail.dat” files instead of normal email attachments. From the perspective of the email recipient, the recipient receives an email message that was supposed to have some attachments like word processor files or PDF files. And instead the email message has one attachment called “winmail.dat”. The winmail.dat file is unreadable.
When this problem happens, the fault lies with the sender, who (a) is using Microsoft Outlook and (b) wrongly assumes that everyone else in the world uses Microsoft Outlook. Microsoft offers a knowledge base article that lists four different ways to remedy this problem. Basically the sender, who uses Microsoft Outlook, is able to configure his or her Outlook so that it generates email attachments that everyone can open, rather than generating email attachments that can only be opened if the recipient is also using Microsoft Outlook.
Sending an event invitation that fails to state the date or time of the event. The way this works is that the recipient receives an email message that talks about some upcoming event — perhaps a telephone conference — and the message rather oddly never gets around to saying what date and time the event will take place. When this problem happens, the fault lies with the sender, who (a) is using a Microsoft Outlook Calendar to send the invitation and (b) wrongly assumes that everyone else in the world uses Microsoft Outlook Calendar.
The problem is that the sender’s email message contains the date and time of the event, but in a proprietary Microsoft format that is visible only to a recipient that happens to be using Microsoft Outlook.
The workaround is for the sender (a user of Microsoft Outlook) who is trying to send a calendar invitation to include the date and time of the event in the body of the email message.