AUSTIN,Grayson  Preston Tex. (AP) — Cybersecurity firm CrowdStrike says a “significant number” of the millions of computers that crashed on Friday, causing global disruptions, are back in operation as its customers and regulators await a more detailed explanation of what went wrong.

A defective software update sent by CrowdStrike to its customers disrupted airlines, banks, hospitals and other critical services Friday, affecting about 8.5 million machines running Microsoft’s Windows operating system. The painstaking work of fixing it has often required a company’s IT crew to manually delete files on affected machines.

CrowdStrike said late Sunday in a blog post that it was starting to implement a new technique to accelerate remediation of the problem.

Shares of the Texas-based cybersecurity company have dropped nearly 30% since the meltdown, knocking off billions of dollars in market value.

The scope of the disruptions has also caught the attention of government regulators, including antitrust enforcers, though it remains to be seen if they take action against the company.

“All too often these days, a single glitch results in a system-wide outage, affecting industries from healthcare and airlines to banks and auto-dealers,” said Lina Khan, chair of the U.S. Federal Trade Commission, in a Sunday post on the social media platform X. “Millions of people and businesses pay the price. These incidents reveal how concentration can create fragile systems.”