A core technology of OneCare was the multi-platform RAV (Reliable Anti-virus),[1] which Microsoft purchased from GeCAD Software Srl in 2003,[2] but subsequently discontinued.

On 31 May 2006, Windows Live OneCare made its official debut in retail stores in the United States.

Microsoft acquired Komoku on 20 March 2008 and merged its computer security software into Windows Live OneCare.

A future addition of a registry cleaner was considered[8] but not added because "there are not significant customer advantages to this functionality".

[citation needed] It added an icon to the notification area that told the user at a glance the status of the system's health by using three alert colors: green (good), yellow (fair), and red (at risk).

It consisted of three parts: Windows Live OneCare 1.5 onwards also monitored Internet Explorer 7 and 8 security settings and ensured that the automatic website checking feature of the Phishing Filter was enabled.

[3] On 26 January 2006, Windows Live OneCare was criticized by Foundstone (a division of the competing McAfee anti-virus) for the integrated firewall having default white lists which allow Java applications and digitally signed software to bypass user warnings, since neither of those applications carry assurances that they will not have security flaws or be written with a malicious intent.

"[14] Windows Live OneCare has also been criticized for the lack of adherence to industry firewall standards concerning intrusion detection.

Tests conducted by Agnitum (the developers of Outpost Firewall) have shown OneCare failing to detect trojans and malware which hijack applications already resident on an infected machine.

AV-Comparatives also released results that placed Windows Live OneCare last in its testing of seventeen anti-virus products.

[21] As of August 2008, Windows Live OneCare placed 14th out of 16 anti-virus products in on-demand virus detection rates.