jackwent wrote:
Has anyone had the experience of one of the Thunderbolt/USB ports ceasing to function with no apparent cause? Using Big Sur 11.6, my MacBook Pro (13-inch, 2016, Four Thunderbolt 3 Ports) has one port that no longer functions. Have you found a solution to correct this beyond having to take it the the Genius Bar for service?
Reboot typically redefines port definition...
However you can try Try resetting NVRAM/PRAM http://support.apple.com/kb/ht1379
(get at least two-three rounds of the chimes when holding the NRAM Reset)
if no resolve—
resetting the SMC https://support.apple.com/en-us/HT201295
Try a SafeBoot https://support.apple.com/en-us/HT201262
You can try running the user Diagnostic...not as definitive as Apple's own AST2 (Apple Service Toolkit) back bench diagnostic, but may kick out an error code.
Use Apple Diagnostics to test your Mac
https://support.apple.com/en-us/HT202731
Learn how to get your Mac fixed and how much it will cost. https://support.apple.com/mac/repair/service
Get your Mac ready for service - Apple Support https://support.apple.com/en-us/HT209095