Delta Air Lines CEO Ed Bastian criticized cybersecurity firm CrowdStrike and software provider Microsoft for their roles in a five-day service disruption that cost the airline $500 million.

Bastian complained that neither company had offered compensation or effective support, blaming CrowdStrike’s flawed software update for causing widespread outages on July 19.

The issues disrupted Delta’s crew tracking system, leading to the cancellation of about 30% of its flights and leaving approximately 500,000 passengers stranded.

Delta has hired the law firm of David Boies to seek compensation but has not yet filed a lawsuit, CNN has reported.

Microsoft did not comment, and CrowdStrike stated it had no further comments.

Written by B.C. Begley