Nearly all devices back online after CrowdStrike outage, CEO says

What they're saying: "I am deeply sorry for the disruption this outage has caused and personally apologize to everyone impacted," Kurtz wrote in his post.

• "While I can't promise perfection, I can promise a response that is focused, effective, and with a sense of urgency."
• "To our customers still affected, please know we will not rest until we achieve full recovery," he added.

The big picture: Experts have called the CrowdStrike outage the largest IT outage in history.

• The outage affected banks, hospital systems, airlines and retailers. One insurer estimates that Fortune 500 companies lost a collective $5.4 billion from the outages.

Catch up quick: CrowdStrike said in preliminary investigation results published Wednesday that "problematic content data" that accidentally landed in a software update caused the outages.

• The company has added new steps to its internal review processes and said it would start staggering the release of all updates across its customers to avoid a repeat situation.

Yes, but: CrowdStrike is likely to face a new round of scrutiny now that the immediate damage from the incident is almost resolved.

• Lawmakers have called on Kurtz to testify on what happened, and the company is facing criticism over its communications strategy.