McAfee really messed up this time as the anti-virus company pushed out a new virus definition update that falsely identifies the critical Windows system file svchost.exe as a virus. Windows XP SP3 PCs running the new 5958 update from McAfee will delete the file, which will results in many problems including repeated reboots, BSODs and networking problems.
McAfee pushed out a virus definition update, 5958, at 14:00 PDT that causes false positive identification of the critical Windows system file svchost.exe. Machines running Windows XP Service Pack 3 using the 5958 definitions will delete the file, causing many key Windows services to fail to start. The Windows file is being mistakenly detected as W32/wecorl.a. Failure to start svchost.exe causes Windows to automatically reboot, hindering repair efforts.
The company has removed the faulty update, but according to Engadget tens of thousands (and possibly much more) computers have been crippled. McAfee has published information on how to fix this mess, but it requires a tech guy to hit each PC in person.