A new McAfee’s update can cause significant performance issues on systems running Windows XP Service Pack 3, according to multiple reports. 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). It contains a false positive which identifies an important Windows binary, “svchost.exe“, as “W32/Wecorl.a“, a virus. As you may already know, svchost.exe is a common system process typically used by multiple legitimate programs on a Windows systems. If you use McAfee’s Anti-virus and have already received a detection for W32/Wecorl.a, don’t restart your computer and immediately perform the remediation steps in this article. Otherwise, your computer will enter a reboot loop and loose all network access. If you are affected, you will see a message with the following information:
The file C:WINDOWS\system32\svchost.exe contains the W32/Wecorl.a Virus.
Undetermined clean error, OAS denied access and continued.
Detected using Scan engine version 5400.1158 DAT version 5958.0000.
In such case, you will have to use the Windows XP Recovery Console or a Windows boot CD to fix this issue. If you don’t know how to do that, then please read how to install and use the Recovery Console in Windows XP first. Once in the recovery console, type the following commands in the console prompt and then press Enter on your keyboard.
copy \windows\system32\dllcache\svchost.exe \windows\system32
If everything goes well, one file will be copied to Windows System32 directory. Now can then type Exit and press Enter to reboot your computer. Your computer should boot up work properly.