USB Not Working in El Capitan

[BoctorBill]

Boctor wrote above:
"I bought a new Mac Mini in Feb 2016 that has always lost all USB power and connectivity after it sleeps for an extended period."

Question:
Are you using a USB hub, by any chance…?

No. I'm connected to a USB keyboard, USB mouse, an ethernet cable, and an HDMI monitor.

 

[stylinexpat]

I get this at times when I connect my iPad or iPhone to my computer to sync via iTunes where it would not connect

 

[BoctorBill]

This problem completely disappeared when I upgraded this machine to macOS Sierra last week. Just gone. I'd done fresh rebuild of it with El Capitan 4 times, and Apple replaced the motherboard twice. When it was software the whole time.
I'm glad it's solved, but it took 7 months after I bought it before it was usable for anything.

 

[stylinexpat]

This problem completely disappeared when I upgraded this machine to macOS Sierra last week. Just gone. I'd done fresh rebuild of it with El Capitan 4 times, and Apple replaced the motherboard twice. When it was software the whole time.
I'm glad it's solved, but it took 7 months after I bought it before it was usable for anything.

I was afraid to upgrade and end up with another problem. Each update brings new problems

 

[BoctorBill]

I was afraid to upgrade and end up with another problem. Each update brings new problems

Yeah, I had reservations, but I backed up the system first and, honestly, it's been useless so I wouldn't have lost anything anyway.

 

[rybskip]

This problem completely disappeared when I upgraded this machine to macOS Sierra last week. Just gone. I'd done fresh rebuild of it with El Capitan 4 times, and Apple replaced the motherboard twice. When it was software the whole time.
I'm glad it's solved, but it took 7 months after I bought it before it was usable for anything.

I would genuinely like to attempt this solution, but Apple has locked out my early 2008 iMac. To use macOS Sierra, I would have to buy a more recent iMac. Other than the irritation of having to remove and reinstall the keyboard USB connector when I change an application context, this early 2008 iMac8,1 works perfectly.

I will attempt to downgrade the machine with a full backup of applications and a clean install of OS X 10.10 to see if I can remove this problem. More when I have done this . . . .

rybskip

 

[imorton]

I would genuinely like to attempt this solution, but Apple has locked out my early 2008 iMac. To use macOS Sierra, I would have to buy a more recent iMac. Other than the irritation of having to remove and reinstall the keyboard USB connector when I change an application context, this early 2008 iMac8,1 works perfectly.

I will attempt to downgrade the machine with a full backup of applications and a clean install of OS X 10.10 to see if I can remove this problem. More when I have done this . . . .

rybskip

Have you done the downgrade, as I have this issue also... USB 3.0 Hub issues with El Capitan...