A faulty update from the U.S.-based cybersecurity firm CrowdStrike caused a massive outage for Microsoft Windows-based desktops and laptops around the world on Friday.

Massive Microsoft outage hits flights, banks, stock exchanges, broadcasters

The issue is related to CrowdStrike’s Falcon Sensor, a software designed to prevent computer systems from cyber-attacks, which broke PCs running Windows, causing them to crash and display the Blue Screen of Death (BSOD) error message. Users around the world have been unable to reboot and are stuck in a recovery loop.

This widespread outage has affected banks, airlines, hospitals, media companies, IT institutes, TV broadcasters, supermarkets, and many other businesses worldwide.

CrowdStrike has acknowledged the problem and identified the update affecting its Falcon Sensor product. It has since rolled back the changes and released fixes to address the crashes. However, some Windows hosts continue to encounter the BSOD error message related to the Falcon sensor, leading to unexpected computer shutdowns or restarts.

“CrowdStrike is actively working with customers impacted by a defect found in a single content update for Windows hosts. Mac and Linux hosts are not impacted. This is not a security incident or cyberattack. The issue has been identified, isolated and a fix has been deployed,” George Kurtz, President and CEO of CrowdStrike, said in a post on X (formerly Twitter).

“We refer customers to the support portal for the latest updates and will continue to provide complete and continuous updates on our website. We further recommend organizations ensure they’re communicating with CrowdStrike representatives through official channels. Our team is fully mobilized to ensure the security and stability of CrowdStrike customers,” he added.

CrowdStrike is actively working with customers impacted by a defect found in a single content update for Windows hosts. Mac and Linux hosts are not impacted. This is not a security incident or cyberattack. The issue has been identified, isolated and a fix has been deployed. We…

— George Kurtz (@George_Kurtz) July 19, 2024

Further, CrowdStrike has provided a workaround for affected Windows users to resolve the issue:

* Boot Windows into Safe Mode or the Windows Recovery Environment

* Navigate to the C:\Windows\System32\drivers\CrowdStrike directory

* Locate the file matching “C-00000291*.sys”, and delete it.

* Boot the host normally.

Meanwhile, Microsoft said it is aware of the issue affecting Windows desktops and laptops caused by a recent update to CrowdStrike Falcon Sensor software.

“We anticipate a resolution is forthcoming. We’re aware of an issue affecting Windows devices due to an update from a third-party software platform,” a spokesperson said.