For computers from the early to mid 2010s in particular, the wifi card might be reported as not fitted or working. try these steps.
Reset the SMC Reset the PRAM Remove the file: /etc/sysctl.conf The problem might be wifi/Bluetooth cable, it runs over the disc drive and is prone to failure.
My latest blog post: Sheeple: Are they succumbing to fake news, misinformation, and propaganda. (posted 2025-09-24). My latest podcast: OJB's Podcast 2029-09-09 Kiwi Values.