Dec 2, 2010 17:13 GMT  ·  By

A bad update issued by AVG to its users today crippled numerous computers running Windows 7 64-bit, which failed to boot into the OS after being restarted.

We are sorry to report that we have identified a potential conflict between one of our recent updates (3292) and a significant number of systems running on the Windows 7 64-bit platform that has caused systems to go into an infinite crash loop,” the company announced.

Following the buggy update, affected users rushed to the support forums to report Blue Screens (BSOD) accompanied by error messages reading “the program can't start because %hs is missing.”

Going into Self Mode was not possible, so people were stuck with very few options. Eventually, the company posted detailed recovery steps, but they are definatelly not addressed to non-technical users.

The solution involves downloading and booting from the AVG Rescue CD, which is a Linux environment, and using the File Manager utility to rename avgrs*.exe and avgchsv*.exe from “C:\Program Files\AVG\AVG10\” to something else.

After this procedure, the rescue CD can be removed and the computer should be able to boot back into Windows. However, at this point the AVG installation is damaged.

This is because the entire problem was caused by a wrong update being served for 64-bit systems, which means that multiple files, including .DLLs, have been replaced with wrong versions.

To overcome this and restore proper AVG functionality, users are asked to download the application’s installer, run it and choose “repair installation” as option.

In the AV industry most issues that cause the crash of large number of computers are usually the result of false positive detections involving critical system files.

Back in March, BitDefender dealt with such an incident after a bad definition update caused its 64-bit products to quarantine Windows components.

Later, in April, McAfee dealt with an even bigger problem, when a similarly buggy update left millions of computers unbootable.