Dunamis7 Said:
"MacBook Air only one usb-c port works: [...] Is there a test or diagnostic procedure to test The ports? I have already performed a SMC. Two months out of Warranty when I discovered this issue. Very disappointed after owning Mac's forever."
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What to Try:
Try this following, in the order provided.
A. Single Out this User:
For temporary use and troubleshooting purposes, create a new Administrator User, seeing if all shows up as it should. If so, then it is likely an issue with the current user itself. Once determined, delete this Administrator User.
B. Reset SMC and your NVRAM Thrice:
Sometime, changes (i.e. Update Installations) are made, and then settings (i.e. Finder GUI) become manipulated, technically. So, reset both. Note that this may take three tries just to reset them successfully. It may take some time to perform this. So, be certain you have the time to do so.
Use these Links:
C. Reset Finder:
Note that to reset Finder (so it operates correctly), you have to reinstall the macOS.
D. Reinstall the macOS:
Nothing would be deleted. It's just that items that have become corrupted or deleted, would be replaced or reinstalled back to where they should be. Go Here: How to reinstall macOS from macOS Recovery - Apple Support. Important: Be certain to create a backup of your Mac prior to all of this. That way, you can have something to restore from the Mac from, should anything go wrong with the reinstall.
E. Time Machine Backup:
Important: Prior to the reinstallation, Create a Time Machine Backup of your Mac, so that you can have something to restore your Mac from, should anything go wrong, doing the install.