CrowdStrike has pushed back against Delta Air Lines’ claims that the cybersecurity firm was negligent in the events that led to the recent cancellation of thousands of flights following last month’s significant IT outage,

“CrowdStrike reiterates its apology to Delta, its employees, and its customers, and is empathetic to the circumstances they faced,” wrote CrowdStrike’s lawyer, Michael B. Carlinsky, in an email. “However, CrowdStrike is highly disappointed by Delta’s suggestion that CrowdStrike acted inappropriately and strongly rejects any allegation that it was grossly negligent or committed willful misconduct with respect to the Channel File 291 incident.”

The letter further claimed that CrowdStrike CEO George Kurtz personally offered online assistance to Delta CEO Ed Bastian during the outage, but received no response. Delta later informed the cybersecurity firm that no help was needed, according to the letter.

“Delta’s public threat of litigation distracts from this work and has contributed to a misleading narrative that CrowdStrike is responsible for Delta’s IT decisions and response to the outage,” the letter reads. “Should Delta pursue this path, Delta will have to explain to the public, its shareholders, and ultimately a jury why CrowdStrike took responsibility for its actions – swiftly, transparently, and constructively – while Delta did not.”

On July 19, CrowdStrike released a faulty configuration update for its Falcon sensors, which resulted in around 8.5 million Windows systems crashing and entering reboot loops. This update caused IT outages for CrowdStrike customers worldwide, impacting transportation companies, healthcare services, government agencies, and other organizations.

Delta took significantly longer than most of its competitors to recover, and according to its CEO, it was forced to cancel over 5,000 flights, resulting in an estimated $500 million loss over 5 days.

To that end, Delta hired attorney David Boies to investigate legal options, including a potential lawsuit against CrowdStrike for damages. Boies served as special trial counsel in the Department of Justice’s 1998 antitrust case against Microsoft, which led to Microsoft being found guilty on most charges related to bundling Internet Explorer with Windows. Boies has also represented several other opponents of Microsoft and numerous high-profile clients, like Harvey Weinstein.

“The letter speaks for itself. We have expressed our regret and apologies to all of our customers for this incident and the disruption that resulted. Public posturing about potentially bringing a meritless lawsuit against CrowdStrike as a long-time partner is not constructive to any party. We hope that Delta will agree to work cooperatively to find a resolution,” a spokesperson for the company said in a statement.