According to software giant Microsoft, more than eight million computers have been affected by the "largest IT outage in history".
The company said in a blog post on Saturday that a software update from cybersecurity firm CrowdStrike had affected nearly 8.5 million Microsoft devices.
Worldwide, flights were halted, patients were unable to make appointments, train passengers were delayed and football clubs were unable to sell tickets. In addition, broadcasts from media companies were severely disrupted.
Microsoft said in a Reuters report: "We currently estimate that the CrowdStrike update affected 8.5 million Windows devices, or less than 1 percent of all ...