CrowdStrike Holdings Inc. Chief Executive Officer George Kurtz said in a Thursday LinkedIn post that more than 97% of the company’s Falcon agent sensors that use Windows are now back online.

CrowdStrike sent out a botched software update that crashed millions of computers on July 19, triggering a global IT outage that grounded flights, closed businesses and brought markets to a standstill. The disruption lasted days, wreaking approximately US$5.4bil of havoc on Fortune 500 companies, according to Parametrix. CrowdStrike shares have fallen by about a quarter since the outage.

The company has struggled to fix the problem, which it said was caused by an error in a quality-assurance tool it uses to screen updates. The bug, which the company said wasn’t the result of a cyberattack or security breach, affected more than 8.5 million Windows users, according to Microsoft Corp.

"To our customers still affected, please know we will not rest until we achieve full recovery,” Kurtz wrote in his post.

Mac and Linux machines weren’t impacted by the incident.

 - Bloomberg