Update 2 Problems in updating Kaspersky Lab anti-virus software led to some machines locking up.The Russian anti-virus firm said the problem was due to an error in a threat signature update issued on Thursday, which are now resolved. It apologised for problems caused by the SNAFU, which were severe for those affected.

"This error led to system instabilities and, in some rare instances, to system failure on a limited number of computers with Kaspersky Anti-Virus 7.0, Kaspersky Internet Security 7.0 and Kaspersky Anti-Virus 6.0 for Windows Workstations MP2 and MP3," a statement for Kaspersky explained.

"Unfortunately, the error did not occur when the defective threat signature update was initially installed, but only when the next correct update was performed. Therefore, the error was not detected during internal testing of the defective update and was subsequently sent out to users of the company's products."

The SNAFU affected both consumers and corporate users. Windows PCs bugs hit by the bug after applying the faulty anti-virus definition files displayed the message "previous application launch failed" before becoming stuck in an endless loop. The problem caused all sorts of grief for sys admins administering users running Kaspersky's anti-virus software package, according to forum postings.

Updates reportedly froze 26 per cent of the way through the process. Thereafter machines operate at a snail's pace, forcing users to reboot.

"In the vast majority of cases, users can rectify the error by rebooting their computer. In any other cases, the error can be removed with the assistance of the company's free 24-hour technical support service," Kaspersky advised.

David Emm, senior technology consultant at Kaspersky Lab UK, said Kaspersky developed a resolution for the problem at 10pm GMT (01:00 Moscow time) on Thursday. The exact cause of the glitch is still under investigation.

Kaspersky is working with affected customers in attempting to resolve the any lingering problem. It's unclear how many punters worldwide were affected (quite a few in the Antipodes judging by forum posts). Few, if any, UK users of Kaspersky have been hit because of the timing of the release. Kaspersky said it was reviewing its testing procedures to prevent a repition of the problem.

"Kaspersky Lab deeply apologises for any inconvenience caused to users by the error. The company's technical support service is currently making every effort to minimize its effects. Furthermore, measures will be taken in the nearest future to upgrade the internal testing system for Kaspersky Lab updates, in order to prevent the repetition of any similar errors in future," it said.

Duff anti-virus signature updates are rare but not unprecedented and generally cause far less inconvenience than computer viruses. Nonetheless their very occurrence illustrates some of the pitfalls of the anti-virus scanner approach created by the need for frequent updates. In April 2005, for example, a duff anti-virus signature update from Trend Micro floored the PCs of many who applied it. ®

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