Travellers at Scottish airports have been affected by a global IT outage affecting Microsoft Windows systems on the ‘busiest day’ of the holiday season.

Check-in facilities and security gate operations were affected at both Edinburgh and Glasgow airports this morning after the tech giant was crippled by a software issue overnight.

The Redmond, Washington-headquartered company, which reclaimed top spot as the world’s most valuable firm last month, was unable to deliver its services as a result of the IT error caused by a third party cybersecurity firm.

Many users of Microsoft systems this morning were unable to get past a blue ‘recovery’ screen when logging onto their computers.

At airports around the world, the ‘blue screen of death’, was displayed on flight departure screens, leaving some like at Delhi airport resorting to whiteboard and marker pen.

Microsoft said it had fixed the software patch from third party security vendor CrowdStrike at 5:21am UK time this morning – but not before many travellers had started to arrive at departure lounges. There were scheduled to be 3,200 flights taking off from UK airports today – one flight every 27 seconds – on the busiest day of the tourist season since the pandemic, travel experts said.

Edinburgh airport updated travellers on its X social media account, saying: “An IT system outage means wait times are longer than usual at the airport. This outage is affecting many other businesses, including airports.

“Work is ongoing to resolve this and our teams are on hand to assist where we can. Passengers are thanked for their patience.

“Passengers should not travel to the airport without first checking the status of their flight with their airline.

“The wait at security is currently around one hour due to the outage and our teams are managing this as best they can.”

Glasgow airport said on the social media platform: “We are largely unaffected by the current global IT issues. At present a small number of airlines have moved to manual check-in and some retailers are only accepting cash payments.” Aberdeen airport – owned by the same AGS Airports Ltd operator as Glasgow – posted the same statement.

Individual airlines such as Ryan Air were particularly impacted by the bug. It said: “We’re currently experiencing disruption across the network due to a global third party IT outage which is out of our control. We advise all passengers to arrive at the airport at least three hours before their scheduled departure time.”

More widely, banks and media outlets were also affected by the issue – with Sky News and CBBC taken off air, and also a host of train operators south of the Border affected.

GP systems in England using the EMIS IT system were also impacted, as well as some pharmacy-dispensing services.

Austin, Texas-headquartered CrowdStrike is a specialist in cloud workload protection and endpoint security, threat intelligence, and cyberattack response services.

It is thought that a faulty update to software that automatically detects threats for Microsoft users – a feature designed to enhance their online protection – had caused the outage. The firm was said to have ‘rolled back’ the patch, which led to users logging on to their computers and unable to get past the blue screen.

Even though the issue has now been fixed, representatives of Crowdstrike issued a workaround to allow users to bypass the screen, which went viral on Reddit.

George Kurtz, CrowdStrike CEO, said on X. “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 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 [sic] ensure they’re communicating with CrowdStrike representatives through official channels. Our team is fully mobilized to ensure the security and stability of CrowdStrike customers.”

Industry experts also ruled out a cyberattack.

Dan Card, of BCS, The Chartered Institute for IT and a cyber security expert, said: “People should remain calm whilst organisations respond to this global issue. It’s affecting a very wide range of services from banks to stores, to air travel.

“It looks like a bug to a regular security update, rather than any form of ‘mega cyber attack’, but this is still causing worldwide challenges and is likely to require a large number of people to make manual remedial steps.

“Companies should make sure their IT teams are well supported as it will be a difficult and highly stressful  weekend for them as they help customers of all kinds. People often forget the people that are running around fixing things.”

Microsoft said on its service health status website: “We’re continuing to see an improvement in service availability across multiple Microsoft 365 apps and services. We’re closely monitoring our telemetry data to ensure this upward trend continues as our mitigation actions continue to progress.”