Flight delays and cancellations are expected to continue into the weekend due to a global IT outage, with experts warning it could take weeks for systems to be fully restored.
A flawed update rolled out by cybersecurity firm CrowdStrike caused widespread outages around the world on Friday, canceling flights and trains and paralyzing some health care systems.
A fix for a bug in the update that affected Microsoft Windows PCs was rolled out on Friday afternoon, with the CEO of the company at the centre of the outage warning that it would take "some time" for systems to be fully restored.
George Kurtz also apologized for the events, saying he was "deeply sorry" and making it clear that it was "not a security or cyber incident."
In a technical statement, CrimeStrike said a "sensor configuration" had caused "a logic error," which the company said had been corrected.
Airports in the UK - including London Gatwick, Heathrow Airport, Manchester Airport and Belfast International Airport - stressed that passengers should check with airlines for delays or cancellations before travelling over the weekend.
A London Gatwick spokesman said: "Following previous global challenges, our airport IT systems are now functioning normally and we expect most flights to return to normal tomorrow.
"However, there will still be delays and cancellations tonight and over the weekend. We strongly advise passengers to check with their airline for the latest updates."
A Manchester Airport spokesperson said: "Check-in and boarding for the affected airlines is manual and taking longer than normal, resulting in long queues at check-in.
"Some flights may experience delays and schedules have been affected by issues caused by the effects of the global IT outage at airports around the world. This means that some flights may be cancelled by airlines at short notice."
On Friday, 167 flights scheduled to depart from British airports were cancelled and others were delayed. In addition, 171 flights scheduled to land in the UK were cancelled due to the technical fault.
According to aviation analytics firm Cirium, 5,078 flights were cancelled worldwide on Friday, or 4.6% of scheduled flights, including 167 flights from the United Kingdom.
The National Pharmacy Association warned that disruption to pharmacy services is likely to last into the weekend even when systems are back online, as outlets deal with a backlog of medicine deliveries.
Industry expert Adam Leon Smith from BCS, the Chartered Institute for IT, warned that it could take "weeks" before all computers and systems are fully restored.
"The fix will have to be deployed to many computers around the world. So if computers are getting blue screens and endless loops, it could be more difficult and take days and weeks," he said.
Professor Ciaran Martin, founder and director of the National Cyber Security Centre (NCSC), also said it was difficult to estimate how long it would take to recover from the outage.
"The underlying problem has been resolved and the solutions are being implemented," he said.
The NHS is aware of a global IT outage and an issue with a GP appointment and patient records system.
If you have an appointment, please come unless you have been told otherwise. If you need help, use 111 online or by phone, and in emergencies call 999.
➡️https://t.co/M4QxHP2GqM
- NHS England (@NHSEngland) July 19, 2024
"Some industries can recover quickly. But others, like aviation, will have long lags. That said, I would be surprised if we are still facing serious problems next week."
Experts warned users to "remain vigilant" for potential scams while systems recover.
In a letter to customers and partners, Mr. Kurtz said: "We know that adversaries and malicious actors will attempt to exploit these types of events.
"I encourage everyone to remain vigilant and ensure you contact official CrowdStrike representatives."
The NCSC reported an increase in phishing referring to the outage.
The company's website calls on organizations to take action and advises individuals to be alert to suspicious emails or messages.
"Please note that an increase in phishing referencing this outage has already been observed, as opportunistic malicious actors attempt to take advantage of the situation," the NCSC said.
Shares of CrowdStrike fell when U.S. markets opened on Friday as investors continued to process the fallout from the outage.
Shares fell more than 8% in early trading, knocking about US$10 billion (£7.8 billion) off their market value. The major financial markets in the US and UK fell during the trading session as other companies were also hit.
The flawed update caused critical infrastructure to crash, computer systems to go offline and many devices to display the so-called "blue screen of death" as they became stuck in an endless cycle of attempting to reboot themselves, affecting key sectors across the country.
The outage caused disruption to "most GP practices", NHS England said, with ambulance services also reporting increased pressure on 999 and NHS 111 services due to calls from patients unable to contact other NHS providers because of the IT issues.
Across England, GP practices reported being unable to make appointments or access patient records because their EMIS web system was down.
In the UK, Sky News was briefly taken off air on Friday morning and Britain's largest train operator, Govia Thameslink Railway, warned passengers of disruption due to "widespread IT issues".
Around the world, banks, supermarkets and other large institutions reported computer problems that disrupted services. In addition, many companies were unable to process digital payments or access key databases.
Ann Johnson, Microsoft's deputy chief information security officer, described the outage as "a very significant problem" and could not predict how long it would take for all customers to be back online.
