A major disruption to Windows PCs in the U.S., U.K., Australia, South Africa and other countries was caused by an error in a CrowdStrike update, the cloud security company announced on Friday. Emergency services, airports and law enforcement reported downtime, which is ongoing.

“This is not a security incident or cyberattack,” CrowdStrike said in a statement.

Blue Screen of Death widespread due to CrowdStrike outage

Affected organizations saw the infamous Blue Screen of Death, the Windows system crash alert. According to The Verge, the problem originated with an update to a kernel level driver used to connect CrowdStrike to Windows PCs and servers.

American Airlines, United and Delta flights were delayed on Friday morning due to the issue impacting the airlines’ IT systems. U.K. media outlet Sky News reported on its own television outage early Friday morning. The New Hampshire emergency services department reported it is back online after disruption to 911 services early Friday.

“The issue has been identified, isolated and a fix has been deployed,” CrowdStrike said on Friday. However, outages on some machines that were initially affected are still being reported.

Microsoft 365 reported a service degradation warning on Friday morning, but this appears to be a separate incident.

CrowdStrike made 14.74% of the total software revenue for security software segments and regions in 2023, according to data Gartner sent to TechRepublic by email. Microsoft made 40.16%.

SEE: Downtime costs the world’s largest companies $400 billion a year, according to Splunk.

What steps can businesses take if they are affected by the CrowdStrike outage?

Microsoft recommends restarting Azure Virtual Machines running the CrowdStrike Falcon agent. This may require a lot of reboots, with some users reporting success after as many as 15. Other options are to restore from a backup earlier than July 18 at 04:09 UTC, or to try to repair the OS disk by using a repair VM.”

“Because of the way in which the update has been deployed, recovery options for affected machines are manual and thus limited,” said Forrester VP, Principal Analyst Andras Cser in a prepared statement emailed to TechRepublic. “Administrators must attach a physical keyboard to each affected system, boot into Safe Mode, remove the compromised CrowdStrike update, and then reboot. Some administrators have also stated they have been unable to gain access to BitLocker hard drive encryption keys to perform remediation steps.”

CrowdStrike recommends that its customers keep in touch with CrowdStrike representatives. Organizations, even those not directly affected, should check in with their SaaS partners to see whether they might be experiencing issues.

Because this issue affected so many different organizations, this could be a good time to assess your organization’s reliance on one provider or service, as well as to be sure your organization has a strong recovery process in place. It’s also a time for IT team leaders to make sure their personnel have the support they need.

“This disruption hit on Friday evening in some geographies, right as people were headed home for their weekend,” noted Forrester Principal Analyst Allie Mellen in a prepared statement emailed to TechRepublic. “Tech incidents like this require an all-hands-on-deck approach, and your teams will be working 24/7 over the weekend to recover. Support your teams by ensuring they have adequate support and rest breaks to avoid burnout and mistakes. Clearly communicate roles, responsibilities, and expectations.”

When reached for comment, CrowdStrike directed TechRepublic to the official statement.

This article will be updated as more information becomes available. TechRepublic has reached out to Microsoft for comment.