A flash drive included in this year's Cooper River Bridge Run packets set off alarms Thursday when an antivirus warning popped up on a user's computer screen.

The credit-card-size USB flash drive was included as an alternative to mailing the event's 66-page magazine to each registrant.

One woman tried to read the flash drive Thursday and it activated an antivirus warning message. Not only did her company's antivirus software pop up a warning on her screen, it then erased two HTML files on the USB card - files that were flagged as being infected.

An antivirus vendor's website described the warning as having been triggered by a generic variant of a virus that can infect HTML files and cause malicious websites to be opened by browsers.

Race director Julian Smith said he has spoken with the vendor that manufactured the digital magazine and was assured that there is no virus or malware on the card.

Smith has mailed out 10,000 race packets so far and said he has received a couple calls about the virus warning.

The manufacturer told Smith the card might trigger an antivirus alert because it contains a file that is supposed to run automatically when it is inserted into a USB port. Some antivirus software will ignore the files. Other software may trigger a prompt that asks the user to allow a file to be opened. The manufacturer said the file is safe to open, Smith said.

Those whose antivirus software is set to erase suspicious files should avoid using the drive or disable their antivirus software before trying to read it.

More than 35,000 people have registered for the bridge run, which will be held April 5.