Microsoft Security Essentials

The free antivirus Microsoft gave Windows XP, Vista and 7 users in 2009, retired with Windows 7 in January 2020

Shut down
19902026

Microsoft Security Essentials (code-named Morro) was a free antivirus and anti-spyware program for Windows XP, Vista and 7, released on 29 September 2009 to replace the paid Windows Live OneCare. It passed 30 million users within a year and was folded into Windows 8 as Windows Defender. Microsoft ended support on 14 January 2020 alongside Windows 7, later extending definition updates for existing installations.

Timeline [edit]

  1. 2009
  2. 29 September 2009 Launch
    Microsoft Security Essentials released

    Free for XP, Vista and 7 in 19 countries.

  3. 2010
  4. 29 September 2010 Peak
    30 million users
  5. 2012
  6. 26 October 2012 other
    Windows 8 ships with Windows Defender

    MSE not offered for the new system.

  7. 2019
  8. 11 December 2019 Shutdown announced
    End of support set for 14 January 2020
  9. 2020
  10. 14 January 2020 Shutdown
    End of service with Windows 7

    Download withdrawn; definitions continue for a while.

The site through time

Browse microsoft.com/security_essentials as it was, via the Internet Archive's Wayback Machine:

2009 2011 2013 2015 2017 2019 2020 Full archive →

Ownership [edit]

Microsoft 2009–2020 Founded Replaced Windows Live OneCare; folded into Windows Defender from Windows 8

Key figures [edit]

MetricValueAs ofConfidence
Registered accounts ▲ 30 million 29 September 2010 Reported Users announced by Microsoft after one year

Confirmed official figures · Reported media, cites a source · Estimated analyst or our estimate

Why it shut down [edit]

Official line: Microsoft Security Essentials reached end of service on 14 January 2020, the day Windows 7 did; the download was withdrawn and the program stopped receiving platform updates, though after protests Microsoft agreed to keep sending virus definitions to installed copies for a while longer. Windows 8 and 10 had shipped since 2012 with the same engine built in as Windows Defender, so MSE had been a Windows 7 product for years.

Our analysis: Security Essentials was Microsoft's answer to the paid antivirus industry and to the malware plague of the Windows XP years: a free, quiet, competent scanner that did not nag or expire. It was popular enough, 30 million users in its first year, that Microsoft simply built it into Windows 8 as Defender, which made the separate product redundant. It lived on only because Windows 7 did, and it was retired on the same day.

History [edit]

Morro

Windows Live OneCare, Microsoft's paid security suite, had not sold, and in November 2008 Microsoft said it would replace it with a free, stripped-down anti-malware program, code-named Morro. Microsoft Security Essentials came out on 29 September 2009 for Windows XP, Vista and 7 in 19 countries, after a beta the previous June: real-time protection against viruses, spyware, rootkits and trojans, using the same engine and definitions as Microsoft's business products, with a small footprint, no subscription and no upsell. It required a genuine Windows licence and nothing else. Reviewers were surprised by how good it was, and the antivirus industry complained.

A year later, on 29 September 2010, Microsoft said MSE had more than 30 million users, and it made it available to small businesses on up to ten PCs. Version 2 (December 2010) added network inspection and a Windows Firewall integration; version 4 (2012) was the last major release. In October 2012 Windows 8 shipped with the same protection built in as Windows Defender, and MSE was no longer offered for the new system.

Retired with Windows 7

MSE thereafter was a Windows 7 program, and Microsoft tied its end to Windows 7's: on 14 January 2020 both reached end of support, the MSE download was withdrawn and the program was told it would receive no more updates. In December 2019 Microsoft had said definitions would stop as well; after users and press objected, it said signature updates would continue for installed copies, and they did for some years. Windows Defender, renamed Microsoft Defender Antivirus, is the successor.

The domain today

microsoft.com/security_essentials redirects to a support page saying that Microsoft Security Essentials reached end of service on 14 January 2020 and is no longer available for download.

Similar projects

Windows Live Writer The blog editor bloggers loved, from Onfolio to Windows Essentials 2012, abandoned by Microsoft and rescued as open source 2006–2017 Microsoft Bob A cartoon house instead of a desktop, sold for one year in 1995 1995–1996 Google Desktop Google search for your own hard drive, plus a sidebar of gadgets, retired when the cloud made it pointless 2004–2011 Windows Movie Maker The free video editor a generation learned on, dropped by Microsoft in 2017 2000–2017 Aperture Apple's professional photo manager, the first of its kind, dropped for Photos and finally unable to launch 2005–2015 Microsoft FrontPage The web editor that built a generation of home pages, bought from Vermeer in 1996 and retired in 2006 1995–2006

Sources [edit]

  1. Microsoft's new tool in the fight against malware free to consumers Microsoft 28 September 2009
  2. MS opens up Security Essentials downloads from today The Register 29 September 2009 [archived]
  3. Microsoft Security Essentials racks up 30 million users TechRadar 29 September 2010 [archived]
  4. Windows 7 protection: Microsoft Security Essentials support ends on January 14, 2020 gHacks 11 December 2019 [archived]
  5. Microsoft Security Essentials to get updates after Windows 7 EoS BleepingComputer 18 December 2019 [archived]
  6. What is Microsoft Security Essentials? Microsoft Support 14 January 2020

Last verified: 18 August 2026. Spotted an error? Suggest an edit (corrections with sources are reviewed and applied).