I've waded through the second item on your generic list (before posting originally), and it's taken forever. Of course, no dice, jumping through hoops for nothing, probably making things worse.
Everything has worked fine (for years) until iTunes 12.5.1 deleted my entire library off my iPod when I clicked "sync" (there's not ONE song left!!) and now won't recognize any iPod or iPhone. I've tried every USB port, different Apple cables...(even though logic says it would be impossible for ALL of those things to fail at once on their own...) One thing changed: I auto-updated my iTunes. Apple software robo-updates it "for you."
Call me crazy, but I'm dreaming of a world where the richest corporation on Earth takes the time to release stable, reliable software in the first place, instead of disabling my Apple devices completely & me wasting days of my valuable time randomly trying everything under the sun...not to mention silent training runs when I've spent years building my music library...until Apple finally releases an update and the troubles go away anyway? Who knows...
And somehow "connecting" with other Apple users is going to fix what Apple didn't take care of in the first place!?!? I can Google what's wrong...and the same trouble is all over the Web.
No, no, NO, this is NOT OK. Apple doesn't upgrade software because of a pressing need, it's to increase some perceived financial potential. There wasn't some huge thing that needed to be fixed. This is tweaking for sport, and the cost is coming out of all of us.
Could NOT B more upset. Apple needs to FIX THIS.