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Windows PCs crashing worldwide due to CrowdStrike issue
(mashable.com)
This is a most excellent place for technology news and articles.
It's software put on every machine so that the company can quickly isolate it if/when something bad happens (or it falls out of security compliance). To do this is requires a constant Internet connection, insanely high privileges on the machine and frequent updates to be appraised of risks.
That risk update went off the rails and into the next state.