Anti-virus program McAfee caused computers world-wide to malfunction on Wednesday due to a bug within the software, but the virus outbreak had minimal effects on Harvard computers.

According to Senior Client Technology Advisor Noah S. Selsby ’94, the problem was caused by McAfee’s software update and targeted only Windows XP with Service Pack 3. The bug misidentified a harmless file and caused computers to lock down and reboot repeatedly.

The anti-virus program malfunction affected companies, hospitals, and schools around the world, but had little impact on the Harvard community.

As of yesterday, approximately 20 students requested assistance with locked computers, Selsby said.

The McAfee malfunction did not affect any computers in Harvard facilities because FAS IT had been coordinating a test run of a new anti-virus software program at the time. According to Selsby, the program will be released soon, as FAS IT is in the final stages of negotiation with the software’s vendor.

“We are about to finish a head-to-head product comparison, having chosen another product to replace McAfee which we will announce in the coming months,” Selsby said.

Since the problem with the McAfee virus was detected Wednesday afternoon, FAS IT has worked both internally and with the McAfee company to resolve the problem. FAS IT also issued a public statement containing instructions for preventing the bug at 5:10 p.m. by e-mail.

“A solid anti-virus program is only a part of the complete plan that we take to minimize risk to our faculty, staff and students,” Selsby said. “We also make a great effort...to educate [students] on how to set up their computers’ security settings in order to minimize attacks on their machines.”

The McAfee bug can potentially affect hundreds of thousands of computers across the nation, according to reports from the tech blog Gizmodo.