Outlook Express was an email and network news client produced by Microsoft for its Windows platforms, with versions for other platforms as well. Outlook Express was distributed at no additional cost with Microsoft Internet Explorer, and was thus included in the latest operating systems in the Windows XP and Windows NT families.
It was a program derived from Microsoft Outlook (which is part of Office), but specialized in email and network news, so it did not include groupware features. Instead, it allowed better handling of some features common to email and network news groups, such as text handling.
As of September 1, 2009, it was no longer operational and was replaced by the Windows Mail client (included in Windows Vista), which in turn was replaced by Windows Live Mail (part of the Windows Live Essentials download package).
Storage
Messages in .eml format were stored in a database with the .dbx extension, which only allowed a maximum of 2 gigabytes per file. This database also experienced corruption problems, to such an extent that a group of people developed an open-source program to resolve this issue.
Security features
These multimedia capabilities, combined with the preview feature, allowed the proliferation of worm-type computer viruses that spread through this program simply by modifying its default behavior. To avoid these problems, it was recommended to use it only in text mode, or to use alternative MUAs.
Thus, it was always recommended to configure the program to prevent the display of active content, especially the use of ActiveX in messages, which are particularly dangerous. This could be done by disabling the preview pane and configuring Internet Explorer so that Outlook Express would warn the user of the presence of ActiveX and display a prompt asking whether to allow it to run. This allowed the user to authorize its execution only when it was truly necessary, and only when the message's creator was trustworthy.
Steps to view email headers in Outlook Express
- Open Outlook Express
- Right-click the email you want to inspect and select “Propiedades“
- Select the “Detalles” tab and click the “Origen del mensaje“ button