The software problem that affected systems around the world took New Hampshire’s 911 system offline for a while Friday, delayed or canceled a few flights at Manchester airport, and disrupted hospitals and the states’ court system.

“At its height it impacted approximately 20% of our individual computers, desktops and laptops, and around 20% of servers,” said Av Harris, spokesperson for the New Hampshire Judicial System. “As of early afternoon, all servers are back online, and we restored usability of about 2/3 of the computer units that were out. Working on this throughout the weekend, we do expect to be fully operational by Monday morning.”

The problem shut down all modern Microsoft systems, which prevented everything from scheduling hearings to monitoring search warrants.

Manchester-Boston Regional Airport reporting one flight cancelled and several delayed but that airport operations were unaffected.  American Airlines, Delta Airlines and United Airlines grounded all flights for a while because they couldn’t process tickets.

“We would ask anyone who’s flying out to please check with their airlines for the most up-to-date information,” Manchester-Boston Regional Airport spokeswoman Christina Lawson said Friday morning.

The state’s 911 system was also affected beginning shortly after midnight. “New Hampshire 911 telecommunicators reported that they could see incoming 911 calls on their computer systems, but they were unable to answer those calls,” said a statement from the N.H. Department of Safety.  “As of 3:30 a.m., calls and texts to 911 are being received normally on the New Hampshire 911 backup system.”

All these problems were caused when giant cybersecurity company CrowdStrike sent out a flawed update to an anti-virus signature file used by Microsoft system as part of Falcon Sensor, a cloud-based security service that it described as providing “real-time threat detection, simplified management, and proactive threat hunting.” This error made Falcon Sensor flag some important files in Microsoft systems as a virus, shutting down the systems.

Ironically, being out of date was a protection. That’s why, for example, Southwest Airlines wasn’t hurt; It hasn’t upgraded its systems from Windows 3.1, which is so old that it can’t use the cloud-based systems which caused the problem.

"This is a a very, very uncomfortable illustrat ion of the fragility of the world’s core internet infrastructure,” Oxford University Prof. Ciaran Martin, former head of the UK National Cyber Security Centre, to ld Reuters news service.

In what sounds like a joke, one of the solutions to being shut out of systems was to turn them on and off as many as 15 times, in hopes that Microsoft would reboot before CloudStrike could mistakenly flag system files as being a virus.