Outlook Express, formerly known as Microsoft Internet Mail and News, is a discontinued

email Electronic mail (usually shortened to email; alternatively hyphenated e-mail) is a method of transmitting and receiving Digital media, digital messages using electronics, electronic devices over a computer network. It was conceived in the ...

and

news client A newsreader is a software application that reads articles on Usenet distributed throughout newsgroups. Newsreaders act as clients which connect to a news server, via the Network News Transfer Protocol (NNTP), to download articles and post new ...

included with

Internet Explorer Internet Explorer (formerly Microsoft Internet Explorer and Windows Internet Explorer, commonly abbreviated as IE or MSIE) is a deprecation, retired series of graphical user interface, graphical web browsers developed by Microsoft that were u ...

versions 3.0 to 6.0. As such, it was bundled with several versions of

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

, from

Windows 98 Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the second operating system in the 9x line, as the successor to Windows 95. It was Software ...

Windows Server 2003 Windows Server 2003, codenamed "Whistler Server", is the sixth major version of the Windows NT operating system produced by Microsoft and the first server version to be released under the Windows Server brand name. It is part of the Windows NT ...

, and was available for Windows 3.x, Windows NT 3.51,

Windows 95 Windows 95 is a consumer-oriented operating system developed by Microsoft and the first of its Windows 9x family of operating systems, released to manufacturing on July 14, 1995, and generally to retail on August 24, 1995. Windows 95 merged ...

, Mac System 7,

Mac OS 8 Mac OS 8 is the eighth major release of the classic Mac OS operating system for Macintosh computers, released by Apple Computer on July 26, 1997. It includes the largest overhaul of the classic Mac OS experience since the release of System 7 ...

, and

Mac OS 9 Mac OS 9 is the ninth and final major release of the classic Mac OS operating system for Macintosh computers, made by Apple Computer. Introduced on October 23, 1999, it was promoted by Apple as "The Best Internet Operating System Ever", highlight ...

. In

Windows Vista Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, released five years earlier, which was then the longest time span between successive releases of Microsoft W ...

, Outlook Express was superseded by

Windows Mail Mail (later Microsoft Outlook) is a discontinued email client developed by Microsoft and included in Windows Vista and later versions of Windows. It was available as the successor to Outlook Express, which was either included with, or released f ...

. Outlook Express is a different application from

Microsoft Outlook Microsoft Outlook is a personal information manager software system from Microsoft, available as a part of the Microsoft 365 software suites. Primarily popular as an email client for businesses, Outlook also includes functions such as Calendari ...

. The two programs do not share a common codebase, but they do share a common architectural philosophy. The similar names lead many people to conclude incorrectly that Outlook Express is a stripped-down version of Microsoft Outlook. Outlook Express uses the Windows Address Book to store contact information and integrates tightly with it.

History

Version 1.0 was released as ''Microsoft Internet Mail and News'' in 1996 following the

Internet Explorer 3 Microsoft Internet Explorer 3 (IE3) is the third version of the Internet Explorer graphical web browser which was announced in March 1996, and was released on August 13, 1996 by Microsoft for Microsoft Windows and on January 8, 1997 for Apple Ma ...

release. This add-on precedes the ''Internet Mail'' profile for Microsoft Exchange 4.0 bundled in

. Version 2.0 was released at the end of 1996. Internet Mail and News handled only

plain text In computing, plain text is a loose term for data (e.g. file contents) that represent only characters of readable material but not its graphical representation nor other objects ( floating-point numbers, images, etc.). It may also include a lim ...

and rich text ( RTF) email, lacking HTML email. In 1997 the program was changed and renamed to ''Outlook Express'' and bundled with

Internet Explorer 4 Microsoft Internet Explorer 4 (IE4) is the fourth version of the Internet Explorer graphical web browser that Microsoft unveiled in Spring of 1997, and released on September 22, 1997, primarily for Microsoft Windows, but also with versions availa ...

. The Windows executable file for Outlook Express, ''msimn.exe'', is a holdover from the Internet Mail and News era. Like Internet Explorer, Outlook Express 4 can run on Mac System 7, OS 8, and OS 9.

Internet Explorer 5 Microsoft Internet Explorer 5 (IE5) is the fifth version of the Internet Explorer graphical web browser, the successor to Internet Explorer 4 and one of the main participants of the first browser war. Its distribution methods and Windows integ ...

required Outlook Express 5 to save Web Archive files (see

MHTML MHTML, an initialism of "MIME encapsulation of aggregate HTML documents", is a web archiving file format used to combine, in a single computer file, the HTML code and its companion resources (such as images) that are represented by external hyp ...

). Outlook Express 6 is the last version of the software with Outlook branding. It has a similar layout to Outlook Express 5. It was included with Windows XP.

Supported file formats

* .DBX - Outlook Express Email Folder *.EMAIL - Outlook Express Email Message * .EML - E-Mail Message * .IDX - Outlook Express Mailbox Index File * .MBX - Outlook Express Mailbox * .MIM - Multi-Purpose Internet Mail Message File * .MIME - Multi-Purpose Internet Mail Extension * .MS-TNEF - MS Transport Neutral Encapsulation Format * .NCH - Outlook Express Folder File * .ODS - Outlook Express 5 Mailbox (not to be confused with

OpenDocument The Open Document Format for Office Applications (ODF), also known as OpenDocument, standardized as ISO 26300, is an open file format for word processor, word processing documents, spreadsheets, Presentation program, presentations and ...

spreadsheet file) * .OEB - Outlook Express Backup Wizard File * .PAB - Personal Address Book * .PST - Outlook Personal Information Store File * .SIG - Signature File * .VCF - vCard File * .WAB - Windows Address Book

Versions for Windows

* Microsoft Internet Mail and News 1.0 was released in 1996 with

. * Microsoft Internet Mail and News 2.0 was released later in 1996. * Outlook Express 4.0, which was included in

(June 1998) and integrated with

, stored messages in *.mbx files (similar to the

Mbox Mbox is a generic term for a family of related file formats used for holding collections of email messages. It was first implemented in Research Unix, Fifth Edition Unix. All messages in an mbox mailbox are Concatenation, concatenated and store ...

format used in

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

-based systems). * Outlook Express 5.0, which was included in Windows 98 Second Edition (SE) (June 1999) and integrated with

, switched to *.dbx files, with a separate file for each mailbox folder. * Outlook Express 5.01 was included in

Windows 2000 Windows 2000 is a major release of the Windows NT operating system developed by Microsoft, targeting the server and business markets. It is the direct successor to Windows NT 4.0, and was Software release life cycle#Release to manufacturing (RT ...

(February 2000) and integrated with Internet Explorer 5.01. * Outlook Express 5.5 was included in

Windows Me Windows Me (Millennium Edition) is an operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It was the successor to Windows 98, and was released to manufacturing on June 19, 2000, and t ...

(June 2000) and integrated with Internet Explorer 5.5. * Outlook Express 6.0 was included in

Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct successor to Windows 2000 for high-end and business users a ...

(October 2001) and integrated with

Internet Explorer 6 Microsoft Internet Explorer 6 (IE6) is a web browser developed by Microsoft for Windows operating systems. Released on August 24, 2001, it is the sixth, and by now discontinued, version of Internet Explorer and the successor to Internet Explorer ...

Versions for Mac

* Outlook Express 4.0 was included in Microsoft Office 98 Macintosh Edition. * Outlook Express 5.01 was integrated with

. * Outlook Express 5.01 was bundled with Internet Explorer 5.01. * Outlook Express 5.5 was bundled with Internet Explorer 5.5.

Replacements

Builds of "Outlook Express 7" appeared in early builds of

when in development as "Longhorn". It relied on

WinFS WinFS (short for Windows Future Storage) was the code name for a canceled data storage and management system project based on relational databases, developed by Microsoft and first demonstrated in 2003. It was intended as an advanced storage subsy ...

for the management and storage of contacts and other data. The final version of Vista included a successor to Outlook Express known as

Windows Mail (Vista) Mail (later Microsoft Outlook) is a discontinued email client developed by Microsoft and included in Windows Vista and later versions of Windows. It was available as the successor to Outlook Express, which was either included with, or released f ...

Criticism

Email standards

Beginning with the text-based Unix Mail command, email traditionally used the inline or bottom

posting styles When a message is replied to in e-mail, Internet forums, or Usenet, the original can often be included, or "quoted", in a variety of different posting styles. The main options are interleaved posting (also called inline replying, in which the d ...

when replying to messages. Outlook Express, as well as

Lotus Notes HCL Notes (formerly Lotus Notes then IBM Notes) is a proprietary collaborative software platform for Unix ( AIX), IBM i, Windows, Linux, and macOS, sold by HCLTech. The client application is called Notes while the server component is branded ...

and Microsoft Outlook, top-post (show replies newest to oldest) by default. Microsoft Outlook and Microsoft Exchange use a

proprietary {{Short pages monitor