Update: McAfee software bug takes down thousands of University of Michigan Health System, Eastern Michigan University computers

U-M was just one major institution among thousands of users affected nationwide Wednesday when the McAfee antivirus software update went out. Eastern Michigan University computers were also affected, according to a statement posted on the university's website.

The statement also asked users who could access the Internet to pass along a message to those who could not access the Web to shut their machines down until a fix had been tested.

Late in the workday, U-M circulated a message about a fix for the problem that began with a mass anti-virus software update. The fix for U-M employees only called for them to reboot their computer to allow a central system to run the software fix for them.

Recipients of the e-mail were asked to verbally communicate the message to their colleagues who were unable to access their e-mail.

• See the Twitter buzz about the problem at twitter.com/#search?q=mcafee.

U-M computer staff members were able to remotely stop the update before it affected additional users, U-M Health System spokeswoman Kara Gavin said.

In all, about 8,000 of 25,000 computers in the system were taken offline by the problem, she said.

No patient care was was compromised Wednesday because enough computers remained running to perform necessary functions, she said. Some areas did have to use paper or share computers.

St. Joseph Mercy hospital in Superior Township was not affected by the problem.

In a statement, McAfee apologized for the inconvenience and said a fix was available for the problem.

"In the past 24 hours, McAfee identified a new threat that impacts Windows PCs," the statement said. "The research team created detection and removal to address this threat. The remediation passed our quality testing."

Tina Reed covers health and the environment for AnnArbor.com. You can reach her at tinareed@annarbor.com, call her at 734-623-2535 or find her on Twitter @TreedinAA.