As a result, roughly 8.5 million systems crashed and were unable to properly restart[1] in what has been called the largest outage in the history of information technology[2] and "historic in scale".

[15][16] Almost immediately, Windows virtual machines on the Microsoft Azure cloud platform began rebooting and crashing,[17] and at 06:48 UTC, Google Compute Engine also reported the problem.

[31][23] If crashes persisted, remediation required booting into safe mode or the Windows Recovery Environment and deleting any .sys file beginning with C-00000291- and with timestamp 04:09 UTC in the %windir%\System32\drivers\CrowdStrike\ directory.

[38] Outages were experienced worldwide,[2][39][40] reflecting the wide use of Microsoft Windows and CrowdStrike software by global corporations in numerous business sectors.

China, which has striven toward self-sufficiency in IT, saw little impact to key services such as airlines and banks, although foreign businesses and luxury hotels in the country were affected.

[83] Air India and SpiceJet said that none of its flights were cancelled due to the outage, attributing it to their robust cyber system however, minute delays were reported.

[88] ENAIRE's Aena, the Spanish national airport traffic control manager, mentioned an IT outage in their website and social media.

[92] Berlin Brandenburg Airport announced that since around 07:00 (UTC+2), operational processes were affected by "IT problems at an external provider", and that they planned to stop flights until 08:00 UTC.

[99] Ryanair's booking and check-in services were unavailable and the airline was "forced to cancel a small number of flights", advising passengers to arrive at airports at least three hours before departure.

This disruption, occurring at the peak of the tourist season, resulted in chaotic scenes as passengers were forced to wait for hours for their flights.

[114] In the mid-morning of Friday 19 July, a ground stop was issued by United, Delta, and American Airlines, halting takeoffs but allowing aircraft aloft to reach their destinations.

[125][127] Delta CIO Rahul Samant said the program had been brought back online around 11 a.m. on 19 July, but was overwhelmed by the backlog of updates awaiting processing and had been trying to catch up ever since.

[137] The flight delays meant that many people who had traveled to the 2024 Republican National Convention—which concluded the day the outages started—were stuck in the convention's host city of Milwaukee, Wisconsin.

[41] Numerous Singaporean companies, including Singapore Exchange (SGX) and DBS Bank, reported various levels of service difficulties throughout 19 July.

[167] In the United States, there were outages in 911 service or disruptions in 911 call centres' operation in some parts of Alaska,[168] Arizona,[169] Florida,[170] Iowa,[171] Indiana,[172] Kansas,[173] Michigan,[174] Minnesota,[175] New York,[176] Ohio,[177] Oregon,[178] Pennsylvania,[179] and Virginia.

[190] The Washington Metro Area Transit Authority suffered minor service delays in the early morning in America; their website/live tracking was unavailable until around 9:30 am on 19 July.

[16] University Health Network experienced technical issues in Canada, saying hospitals' clinical activity would continue but warning that appointments may be delayed.

[189] A number of other Canadian hospitals faced difficulties, with Newfoundland and Labrador Health Services activating contingency plans as patient record systems were affected.

[208] England's National Health Service (NHS) said that the issues are "causing disruption in the majority of [English] GP practices",[27] with some of its services, such as GP surgeries, which rely on a software product called EMIS Web, unable to view and manage medical records, issue and manage prescriptions, or make appointments.

[54] The Spanish regional governments of Aragon, Basque Country, Castilla-La Mancha, Catalonia, and Galicia reported problems with their healthcare services.

[212] Hospital Fernando Fonseca [pt] in Portugal reported problems,[213] while the Catholic Health system in New York experienced outages that caused delays in services.

[58] The Central Health information system in Croatia was affected, although it was clarified that it was due to a concurrent issue tied with moving their servers to a new location.

[158] The issue affected the office laptops of DPG Media Belgium – which impacts JOE and QMusic Radio, banks, post services, and government agencies.

[39] Ticketing at Docklands Stadium for Friday night's Australian Football League match between the Essendon Bombers and the Adelaide Crows was affected.

[252] CrowdStrike warned that malicious actors might try to pose as its staff or independent researchers claiming to help fix the problem.

[257] A parody website named ClownStrike was created in the aftermath of the incident; CrowdStrike later sent a Digital Millennium Copyright Act (DMCA) takedown notice to the owner of the site.

The National Coordination Mechanism was activated; Prime Minister Anthony Albanese said, "I understand Australians are concerned about the outage that is unfolding globally and affecting a wide range of services.

[264] Cybersecurity consultant Troy Hunt called the incident the "largest IT outage in history", adding: "This is basically what we were all worried about with Y2K, except it's actually happened this time".

[140] Conversely, cybersecurity expert Andrew Plato argued that monocultures are a net positive, “from a security perspective, there’s actually a lot of benefits to running a smaller, standardized set of software, because it allows you to spot a problem quicker and easier.

[284] In an interview with Wired, cybersecurity consultant Jake Williams said that this outage has "shown why pushing updates without IT intervention is unsustainable," and that "people may now demand changes in this operating model.