Microsoft's Windows Live OneCare was made available to users at the end of January 2007, concomitantly with the launch of Windows Vista. And since its initial release, OneCare has had everything but an easy ride on XP and Vista. In addition to the mediocre performance of the security solution, OneCare could not even start on some machines running XP SP2. This is why on 25 June 2007, Microsoft provided a tool designed to repair the Windows startup file (Boot.ini). A problem in boot.ini in Windows XP SP2 completely stopped the Windows Live OneCare Antivirus service.

"This tool fixes a problem in the Windows XP startup file (boot.ini) that can affect the Windows Live OneCare Antivirus service and prevent it from starting. If your computer is affected by this problem, you will see the following Action to Take in the Windows Live OneCare screen: Urgent - Turn on Antivirus monitoring (At risk);Windows Live OneCare Antivirus service could not start. (At risk)", Microsoft mentioned in the tool's description.

Microsoft revealed that the OneCare problems are intimately connected with modifications introduced to the default configuration of the Windows XP default kernel boot file. RepairBootIni.exe is essentially meant not to resolve the issue but to restore the original file to an unaltered form. "The problem typically occurs if a third-party tune-up or user interface modification program changes the startup screen that Microsoft Windows XP displays during the boot process. This changes the default kernel file that Windows XP uses to boot, and can prevent the Windows Live OneCare Antivirus service from starting. The Boot.ini repair tool restores this default kernel file and allows the Antivirus service to start," Microsoft added.

Despite the shaky start, Windows Live OneCare was recently recertified by the West Coast Labs and the ICSA Labs and also got the VB100 award from Virus Bulletin.