Outlook Express
| Outlook Express | |
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 A screenshot of Outlook Express in Windows XP. |
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| Developer: | Microsoft |
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| Latest release: | 6.00.2900.2180 (Windows XP SP2) / August 3, 2004 |
| OS: | Microsoft Windows (discontinued), Mac OS (unsupported) |
| Genre: | E-mail client, News client |
| License: | Freeware |
| Website: | Outlook Express |
Outlook Express is an e-mail/news client that is included in versions of Microsoft Windows from Windows 98 to Windows XP Service Pack 2 (SP2). It was also bundled with Internet Explorer 4.0, and available for Windows 95 and the classic Mac OS. Microsoft Entourage, which is sold as part of Microsoft Office for Macintosh, has replaced the Mac OS X version.
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Overview
Outlook Express is a different application from the Microsoft Office Outlook e-mail client which ships with Microsoft Office for Windows. The two programs do not share a common codebase, but do share a common architectural philosophy. The similar names lead many people to incorrectly conclude that Outlook Express is a stripped-down version of Microsoft Office Outlook. Outlook Express uses the Windows Address Book to store contact information and integrates tightly with it. On Windows XP, it also integrates with Windows Messenger.
History
Outlook Express is the successor of Microsoft Internet Mail and News, an early e-mail client add-on for Internet Explorer 3.0. Internet Mail and News handled only plain text and rich text (RTF) e-mail, it lacked HTML e-mail.
At one point, in a later beta version of Outlook Express 5, Outlook Express contained a sophisticated and adaptive spam filtering system; however this feature was removed shortly before launch. It was speculated on various websites and newsgroups at that time, that the feature was not stable enough for the mass market. Nearly two years later, a similar system, using a similar method of adaptive filtering, appeared as a feature of Microsoft Office Outlook.
Criticism
E-mail standards
Beginning with the text-based Unix Mail command, E-mail traditionally used the inline or bottom posting styles when replying to messages. Outlook Express, as well as Lotus Notes and Microsoft Outlook, top-post (show replies newest to oldest) by default. The large install base of Microsoft Windows and Microsoft Office has changed perceptions of posting style to the point where users have come to expect the top-posting style and are confused by inline or bottom posting.
Microsoft Outlook and Microsoft Exchange use a proprietary e-mail attachment format called Transport Neutral Encapsulation Format (TNEF) to handle formatting and other features specific to Outlook such as meeting requests. Outlook Express is unable to read this format. It is confusing to users that attachments sent from Outlook are unreadable in Outlook Express.
Database corruption
Outlook Express has been prone to a number of problems which can corrupt its files database, especially when the database increases in size due to increasing number of stored emails and during database compaction. This has led to a thriving market for programs which can backup, restore and recover corrupted files. Microsoft has released documentation which may be able to correct problems and restore access to e-mail messages, without resorting to third party solutions.
However, with latest updates applied, Outlook Express now makes backup copies of DBX files prior to compaction. They are stored in the Recycle Bin. If an error occurs during compaction and messages are lost, the DBX files can be easily restored from the backup.
Security issues
Outlook Express was one of the earlier e-mail clients to support HTML e-mail and scripts. As a result, emails were commonly infected with viruses. Another security flaw previously, was that a script could automatically be opened as an attachment. Another bug was in Outlook Express's attachment handling that allowed an executable to appear to be a harmless attachment such as a graphics file. Opening or previewing the e-mail could cause code to run without the user's knowledge or consent. Outlook Express uses Internet Explorer to render HTML e-mail. Internet Explorer has been widely criticized in the past for having numerous security issues. However, Outlook Express and Internet Explorer both feature security zones to prevent such issues.
With Outlook Express SP2 (part of Windows XP SP2), Microsoft has aimed to correct the security issues. Outlook Express now blocks images inside e-mails by default. It uses only the restricted security zone for HTML e-mail which disables scripts and imposes restrictions on what web content can be rendered. It also warns when opening potentially malicious attachments.
Handling of PGP/MIME signed messages
Outlook Express does not correctly handle MIME, and will not display the body of signed messages inline. Users get a blank e-mail and two attachments (one of the message text and one of the signature) and therefore need to open an attachment to see the e-mail. If the email has been forwarded several times, users need to open attached email messages one inside the other multiple times till they reach the parent e-mail message. This bug has still not been rectified.
Plugins
Outlook Express does not support add-ins as well as Outlook does. There are some objects that were documented in 2003 but are only related to storage. It is not possible to get information about what the user selects or modify user interface. Some companies managed to create their plugins hacking the interface using windows hooks. The most popular was PGP plugin. This add-on was important because the license is GPL so lots of companies learned to create their plugins from this example. Time after, in 2003 some companies provided some commercial solutions to develop add-ins. The most used library is OE API from Nektra.
Support
Outlook Express SP2 is the latest version which is part of Windows XP SP2. Extended support for Windows XP SP2 which covers security hotfixes, will end in 2014.
In October 2005, Microsoft announced that Windows Vista would exclusively include a new application named Windows Mail, based on large parts of Outlook Express source code. Microsoft is also developing Windows Live Mail Desktop, a client for Windows Live services which is a superset of Windows Mail in Windows Vista. Windows Live Mail Desktop will also be available for Windows XP SP2.
Versions and file formats
Outlook Express stores its e-mail messages in different formats depending on the version.
- Outlook Express 4.0, which was included in Windows 98 (June 1998), stored messages in *.mbx files (similar to the MBox format used in UNIX based systems).
- Outlook Express 5.0, which was included in Windows 98 Second Edition (SE) (June 1999), switched to *.dbx files, with a separate file for each mailbox folder.
- Outlook Express 5.0 was included in Windows 2000 (February 2000).
- Outlook Express 5.5 was included in Windows Me (June 2000).
- Outlook Express 6.0 was included in Windows XP (October 2001).
- Outlook Express 6.0 SP2 was included in Windows XP Service Pack 2 (August 2004).