• Home
  • Latest
  • Fortune 500
  • Finance
  • Tech
  • Leadership
  • Lifestyle
  • Rankings
  • Multimedia
TechOutage

Major Microsoft and Crowdstrike disruptions ground planes, banks, McDonald’s stores and the London Stock Exchange

By
Amy Thomson
Amy Thomson
,
Shona Ghosh
,
Vlad Savov
Vlad Savov
and
Bloomberg
Bloomberg
Down Arrow Button Icon
July 19, 2024, 4:23 AM ET
United Airlines was among the major companies to disclose a variety of issues with communications to customer service.
United Airlines was among the major companies to disclose a variety of issues with communications to customer service. Beata Zawrzel—NurPhoto via Getty Images

Computer systems at businesses and public services around the globe were disrupted after a botched update of a widely used cybersecurity program took down Microsoft Corp. systems. 

Recommended Video

CrowdStrike Holdings Inc. Chief Executive Officer George Kurtz posted on X on Friday that the fault had been identified and “a fix has been deployed,” adding that it wasn’t a cyberattack. Compounding the issue, Microsoft also reported an apparently unrelated problem with its Azure cloud service. 

Hitting airlines, banks and healthcare systems, there have been few outages of this scale. The cascading failures underscore vulnerabilities of the modern economy and the central role of security software, which has deep access to operating systems.

“This is unprecedented,” Alan Woodward, professor of cybersecurity at Surrey University, told Bloomberg News. “The economic impact is going to be huge.”

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

The scale of the disruption reflects the enduring ubiquity of Microsoft’s Windows, and the sizeable adoption of CrowdStrike’s security software. Windows is installed on more than 70% of machines, according to StatCounter, and CrowdStrike is the global leader in modern corporate protection software, according to estimates by research firm IDC.

Although its software is designed to thwart threats, CrowdStrike customers posted blue error screens to social media as they were prevented from accessing laptops and corporate computers. 

McDonald’s Corp., United Airlines Holdings Inc., and the LSE Group were among the major companies to disclose issues from communications to customer service. Airports from Singapore to Zurich were impacted. The New York subway said arrival information is unavailable for most of its lines, but services are operating. Bloomberg terminals were operating as normal.

Microsoft said it was “aware of an issue affecting Windows devices due to an update from a third-party software platform.” The company said it fixed a separate glitch affecting Microsoft 365 apps. 

The outages weighed on several sectors, including airlines, insurers and stock exchange operators. Shares in CrowdStrike sank 20%, while Microsoft fell 2.9%.

Past disruptions have been less severe. In 2017, a series of errors within Amazon.com Inc.’s cloud service affected the operation of tens of thousands of websites. In 2021, issues at content delivery network Fastly took out several media networks including Bloomberg News and there were separate disruptions at Amazon’s AWS cloud service.

“I don’t think it’s too early to call it: this will be the largest IT outage in history,” Troy Hunt, an Australian security consultant and creator of the hack-checking website Have I Been Pwned, said in a post on social media platform X.

The first glitches emerged in the US late on Thursday and were blamed on the failure of Microsoft services Azure and 365, the company’s internet-based office software suite. 

Problems linked to CrowdStrike then surfaced hours later in Asia and rippled across systems in Europe. As the US commute got underway, the New York subway said arrival information was unavailable but trains and buses were still running.

Join us at the Fortune Workplace Innovation Summit May 19–20, 2026, in Atlanta. The next era of workplace innovation is here—and the old playbook is being rewritten. At this exclusive, high-energy event, the world’s most innovative leaders will convene to explore how AI, humanity, and strategy converge to redefine, again, the future of work. Register now.
About the Authors
By Amy Thomson
See full bioRight Arrow Button Icon
By Shona Ghosh
See full bioRight Arrow Button Icon
By Vlad Savov
See full bioRight Arrow Button Icon
By Bloomberg
See full bioRight Arrow Button Icon

Latest in Tech

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025

Most Popular

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Rankings
  • 100 Best Companies
  • Fortune 500
  • Global 500
  • Fortune 500 Europe
  • Most Powerful Women
  • Future 50
  • World’s Most Admired Companies
  • See All Rankings
Sections
  • Finance
  • Leadership
  • Success
  • Tech
  • Asia
  • Europe
  • Environment
  • Fortune Crypto
  • Health
  • Retail
  • Lifestyle
  • Politics
  • Newsletters
  • Magazine
  • Features
  • Commentary
  • Mpw
  • CEO Initiative
  • Conferences
  • Personal Finance
  • Education
Customer Support
  • Frequently Asked Questions
  • Customer Service Portal
  • Privacy Policy
  • Terms Of Use
  • Single Issues For Purchase
  • International Print
Commercial Services
  • Advertising
  • Fortune Brand Studio
  • Fortune Analytics
  • Fortune Conferences
  • Business Development
About Us
  • About Us
  • Editorial Calendar
  • Press Center
  • Work At Fortune
  • Diversity And Inclusion
  • Terms And Conditions
  • Site Map

Latest in Tech

zhan, deepak
AIRobotics
Robots are really advancing because they’re learning to think for themselves—and they’re close to figuring out door handles, execs say
By Nick LichtenbergJanuary 6, 2026
12 minutes ago
LawAmazon
Amazon is cutting checks to millions of customers as part of a $2.5 billion FTC settlement. Here’s who qualifies and how to get paid
By Sydney LakeJanuary 6, 2026
2 hours ago
InvestingU.S. economy
Ray Dalio says AI is in ‘the early stages of a bubble,’ so watch out for 2026
By Tristan BoveJanuary 6, 2026
2 hours ago
musk
AISocial Media
Elon Musk’s Grok chatbot draws global backlash for generating sexualized images of women and children without consent
By Kelvin Chan and The Associated PressJanuary 6, 2026
2 hours ago
Databricks CEO Ali Ghodsi speaking on stage at a Fortune tech conference.
AIEye on AI
Want AI agents to work better? Improve the way they retrieve information, Databricks says
By Jeremy KahnJanuary 6, 2026
3 hours ago
C-SuiteSamsung
Why one of the world’s most qualified chief design officers calls Samsung his ‘dream job’
By Nicholas GordonJanuary 6, 2026
3 hours ago

Most Popular

placeholder alt text
Personal Finance
Janet Yellen warns the $38 trillion national debt is testing a red line economists have feared for decades
By Eva RoytburgJanuary 5, 2026
1 day ago
placeholder alt text
AI
Experienced software developers assumed AI would save them a chunk of time. But in one experiment, their tasks took 20% longer
By Sasha RogelbergJanuary 5, 2026
1 day ago
placeholder alt text
Energy
‘Big Short’ investor Michael Burry says toppling of Venezuela’s Maduro will weaken Russia’s global standing as its oil ‘just became less important’
By Marco Quiroz-GutierrezJanuary 5, 2026
1 day ago
placeholder alt text
Success
Blackstone exec says elite Ivy League degrees aren’t good enough—new analysts need to 'work harder' and be nice 
By Ashley LutzJanuary 5, 2026
1 day ago
placeholder alt text
Economy
Under Biden, America got 150 countries to agree a 15% global corporate tax. Under Trump, America gets an exemption
By Fatima Hussein and The Associated PressJanuary 5, 2026
23 hours ago
placeholder alt text
Personal Finance
Current price of silver as of Monday, January 5, 2026
By Joseph HostetlerJanuary 5, 2026
1 day ago

© 2025 Fortune Media IP Limited. All Rights Reserved. Use of this site constitutes acceptance of our Terms of Use and Privacy Policy | CA Notice at Collection and Privacy Notice | Do Not Sell/Share My Personal Information
FORTUNE is a trademark of Fortune Media IP Limited, registered in the U.S. and other countries. FORTUNE may receive compensation for some links to products and services on this website. Offers may be subject to change without notice.