SAN FRANCISCO — Security experts said CrowdStrike's routine update of its widely used cybersecurity software, which caused clients' computer systems to crash globally on Friday, apparently did not undergo adequate quality checks before it was deployed.

The latest version of its Falcon sensor software was meant to make CrowdStrike clients' systems more secure against hacking by updating the threats it defends against. But faulty code in the update files resulted in one of the most widespread tech outages in recent years for companies using Microsoft's Windows operating system.