Update: AVG's press statement regarding this issue after the jump – apparently it doesn't affect the English language version of Windows XP.

A recent update for AVG 7.5 and up (free and paid editions) is causing havoc with some users, who are following the antivirus program’s recommendation to delete a critical system file after being wrongly identified as a Trojan. The file in question is “user32.dll” and its absence will cause a system to either stop booting or go into an endless reboot loop.

AVG says it has fixed the current user32.dll problem and apologized for the mishap on its forums. It also offers help on correcting the problem for those who have already deleted the file, suggesting they try rebooting in safe mode and use the AVG Virus Vault to restore the missing file, or use the Windows XP CD to repair this issue.

This is not the first embarrassing setback AVG has suffered this year. Back in July, the company had to reconfigure its LinkScanner tool after various websites complained about the loads of fake traffic and increased bandwidth costs as a result of the tool’s proactive scanning for malware.

AMSTERDAM, The Netherlands, November 11, 2008 – AVG is actively working to remedy the problem some users are experiencing related to the most recent update to commercial and free versions of AVG 7.5 and AVG 8.0 in some languages. A number of users who installed the update mistakenly received a warning that the Windows system file user32.dll product version 5.1.2600.3099 was infected with a Trojan virus and were prompted to delete a file essential to the operation of Windows XP.

The problem only affects users of the Dutch, French, Italian, Portuguese, and Spanish language versions of Windows XP.

AVG is taking these steps to assist users in remedying the problem:

• Immediate release of a new update to correct the problem.
• Creation of a specific informational section on the AVG website that enables users to resolve the problem.

Affected users should follow the weblinks below for further information and to download the fix tool:

1. http://www.avg.com/support/HotTopics1574 FalsePositiveuser32.dll
2. http://www.avg.com/support/HotTopics1574 FalsePositiveuser32.dll – fix tool

Affected users unable to use their PCs should contact their AVG reseller or ask a friend to download the information and fix tool for them. After running the fix tool, users should run the AVG update program to download and install the correct AVG update.

AVG sincerely regrets the inconvenience users have experienced. We are working to remedy the problem and ensure that any other potential vulnerabilities are identified and eliminated before they can impact users.