McAfee Update Deletes Important Files

Although the problem's been fixed, last week a McAfee virus definition update caused the antivirus product to quarantine or delete Windows applications and other important files.

Last Friday, an update to McAfee’s virus definitions caused the company’s antivirus software to quarantine or delete many Windows applications and other important files. The flawed virus definition update (number 4715) was available for approximately five hours on Friday, March 10, before being withdrawn.

Users who installed the update during that period may have seen everyday applications like Microsoft Excel and Graph, Adobe Acrobat, Macromedia Flash Player, MySQL, and AutoCAD listed as items infected with the virus W95/CTX. Depending on the McAfee product in use and its settings, users may have seen items quarantined (moved to another directory on the system) or deleted outright.

McAfee’s page on the W95/CTX infection includes information on how to restore misidentified files from quarantine. McAfee has posted a substantial list of files incorrectly affected (PDF).

The incident serves to highlight the precarious state of security and antivirus software for the Windows platform, and the necessity of reliable, incremental system and data backups for all computer users.