On Tuesday, US security software company McAfee said it would reimburse home and home office users for any “reasonable expenses” incurred in the wake of its online antivirus-update-gone-wrong last week. It would also extend subscriptions by two years.

What should have been a routine update of virus signatures turned into a nightmare for many Windows XP users last Thursday, causing some PCs to crash, or falling into a cycle of endless restarts.

In a statement posted to its website overnight, US antivirus software company McAfee said it was “committed to reimbursing reasonable expenses” for those hit by its duff online update last week.

The update caused some customers’ computers to crash, or fall into a cycle of endless re-starts.

 The world’s two leading anti-virus software vendors McAfee and Symantec have settled a case with the US Attorney General after renewing customers’ software subscriptions without the customers’ knowledge or authorisation.

Under the settlement announced by US Attorney General Andrew Cuomo in New York, the companies will pay a combined $US750,000 fine as well as offering detailed disclosures to consumers about subscription terms and renewal.

In a move sure to set Symantec and McAfee running to the US Department of Justice, Microsoft has announced it will discontinue its shrinkwrapped commercial antivirus and security product, OneCare, from June 2009, replacing it with a free download program called "Morro".

While OneCare sells for $99, plus $US10 a year to subscribe to a virus update service (around the same price as rival suites from Symantec, McAfee and others), all elements of Morro will be free.