USB Accessories Disabled


macrumors 6502a
Original poster
Mar 25, 2009
Raleigh, North Carolina
Anyone testing iOS 11 B1 or B2 experience that when they connect their device to a Mac using Sierra 10.12.5 they get a message in OS X that, "USB Accessories Disabled: Unplug the accessory using too much power to re-enable USB devices"?

This happened in B1 and now in B2. If I revert the iPad back to 10.3.2 the messages never appear.

I did submit this as a bug report. Wonder if others have it.

This is with my iPad 12.9 second gen on my MBPro 2016 w/ TB connected via USB-C to Lightning.


Jun 23, 2017
My iPhone is no longer detected by iTunes on my Mac, I'm on iOS 11 Beta 2 and macOS High Sierra. There's no message about power at all for me. Not sure if this is the same problem as yours though, as my MacBook is a USB-A MacBook.
The difference with USB-C is that USB-C allows power transfer both ways, so there's a chance your iPad is trying to charge your MacBook or trying to charge with your MacBook.
Last edited:


macrumors newbie
Oct 27, 2017
Chicago, IL
I'm still having this issue with the 2016 touchbar macbook pro 13" and plugging in a 10.5" ipad pro. It's inconsistent, but will be resolved by me unplugging the ipad pro and then plugging it back in. I'm using apple's usb-c to thunderbolt cable as well.

Anyone know of any updates to this, or any solution? Anyone else experiencing this?