A cybersecurity firm says recent updates from Microsoft have caused worldwide IT outages – grounding flights and grinding businesses to a halt.

It’s all because of an update issued by cybersecurity firm Crowdstrike. In the New York City tri-state area, as well as globally, the FAA has issued a ground stop because of ongoing communication issues.

This security update, even though it’s now been rolled back, is affecting communications systems worldwide. No word yet as to when systems will be back online.

Flights across the U.S. are being grounded this morning because of communication issues.

The FAA says Delta, United, and American Airlines have temporarily grounded all flights regardless of their destination, and it’s unclear how long the grounding will last.

Frontier Airlines grounded their flights on Thursday due to a Microsoft outage, but those flights have since resumed. Other U.S. airlines are also reporting difficulties, including with booking, check-in, and other online functions, as are some international airlines including Qantas and Virgin Australia.