Huge problem with my iMac 5K: ALL iPad's disconnect/connect rapidly

[CWallace]

My 2014 iMac 5K did it if my iPad Air 2 was not fully charged, but my 2015 model works fine regardless of how low the battery is on the iPad so maybe the USB chipset / Southbridge changed between them.

 

[ZachsMacDaddy]

Sadly I had the same issue. My fix was to purchase an external USB 3.0 hub... see my thread above for the full story.

I have not had the issues since and use it every day. I connect and disconnect it regularly without any hassles

It's odd that you're using a non powered hub and it fixes it. I would think that the hub you have would still do the same since it's still pulling the same power from the iMac.

 

[dyn]

There are some issues with USB3.0 where the port isn't being set correctly. You can solve that by using a USB2.0 hub or cable or simply a different USB3.0 hub. This doesn't have to be a powered hub.