Microsoft said Saturday that the CrowdStrike update affected 8.5 million Windows devices, less than 1% of all machines that run the software, but the impact is significant because CrowdStrike is widely used by businesses.
The faulty update caused many computer screens to display a blue error screen, rendering them unusable until it was fixed.
CrowdStrike said on Monday that a “significant number” of affected computers had been brought back online and apologized for the disruption.
Figures from data firm OAG showed that 9,650 flights were cancelled between Friday and Sunday. While many airlines recovered, 2,619 flights were cancelled on Sunday, most of them by US airline Delta Air Lines.
The NHS said the system was back online but that “there may still be some delays in restoring services”.
The European Commission went after Microsoft in the early 2000s over concerns that its popular Windows software gave the company an unfair advantage in other areas, such as web browsers.
The company agreed in 2009 to expand computer users’ choices in browsers and other software.
The announcement comes as Apple faces pressure to open up the iPhone due to new European laws, including the requirement that the company allow alternative app stores and web browser engines on the iPhone.
Apple claims the changes make the iPhone less secure.
