There's was trouble packed in with recent McAfee update for Windows XP.
A bad update issued today for McAfee for Windows XP is causing computers worldwide to shutdown and sent itself in a loop of restarts. Engadget received the following statement from McAfee regarding the continuing incident:
McAfee is aware that a number of customers have incurred a false positive error due to incorrect malware alerts on Wednesday, April 21. The problem occurs with the 5958 virus definition file (DAT) that was released on April 21 at 2.00 PM GMT+1 (6am Pacific Time).
Our initial investigation indicates that the error can result in moderate to significant performance issues on systems running Windows XP Service Pack 3.
The faulty update has been removed from McAfee download servers for corporate users, preventing any further impact on those customers. We are not aware of significant impact on consumer customers and believe we have effectively limited such occurrence.
McAfee teams are working with the highest priority to support impacted customers and plan to provide an update virus definition file shortly. McAfee apologizes for any inconvenience to our customers
The story is that the DAT update 5958 deletes the svchost.exe file, which then triggers a false-positive in McAfee itself. Early estimates say that this has affected between 30,000 to 60,000 machines so far.