CrowdStrike's CEO said that more than 97 percent of Windows systems knocked offline by a CrowdStrike update are back online.

Last week, the update caused systems to crash and blue screen of death. This led to flights being canceled, trains being delayed, hospital appointments being scrapped, and more.

Microsoft estimates that some 8.5 million systems were impacted, which would mean around 255,000 Windows computers and servers are still down.

"We understand our work is not yet complete, and we remain committed to restoring every impacted system," CrowdStrike CEO George Kurtz said.

"To our customers still affected, please know we will not rest until we achieve full recovery... I am deeply sorry for the disruption this outage has caused and personally apologize to everyone impacted."

The company faced further criticism this week for sending a $10 Uber Eats gift card to partners as an apology. Many of the cards failed to work.