Delta Air Lines sued cybersecurity company CrowdStrike in a Georgia court after a global outage in July caused mass flight cancellations, disrupted the travel plans of 1.3 million customers and cost carrier more than $500 million ($755.8 million).

Delta’s lawsuit called CrowdStrike’s flawed software update “catastrophic” and said the firm “forced untested and flawed updates on its customers, causing more than 8.5 million Microsoft Windows-based computers worldwide to crash.”

The July 19 incident led to worldwide flight cancellations and hit industries around the world, including banks, healthcare, media companies and hotel chains.

“Delta’s claims are based on debunked misinformation, demonstrate a lack of understanding of how modern cybersecurity works, and reflect a desperate attempt to shift blame for the slow recovery from its failure to modernize its legacy IT infrastructure,” CrowdStrike said in a statement. response to the process.

Delta, which said it had purchased CrowdStrike products since 2022, said the outage forced it to cancel 7,000 flights, impacting 1.3 million passengers over five days.

Delta said CrowdStrike is liable for more than $500 million in out-of-pocket losses, as well as an unspecified amount of lost profits, expenses, including attorneys’ fees, and “reputational harm and future loss of revenue.”

The incident prompted the US Department of Transportation to open an investigation.

“Had CrowdStrike tested the faulty update on even a single computer prior to deployment, the computer would have crashed,” Delta’s lawsuit says.

“Because the faulty update could not be removed remotely, CrowdStrike crippled Delta’s business and created immense delays for Delta’s customers.”

Delta said that as part of its IT planning and infrastructure, it has invested billions of dollars “in licensing and building some of the best technology solutions in the airline industry.”

CrowdStrike asked why Delta fared so poorly than other airlines and said it had minimal liability, which Delta denied.

Last month, a CrowdStrike executive apologized to Congress for the botched software update.

Adam Meyers, senior vice president at CrowdStrike, said the company released a content configuration update for its Falcon Sensor security software that resulted in system crashes around the world.

“We are deeply sorry that this happened and we are determined to prevent this from happening again,” Meyers said.