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  1. #1
    USB DEVICES DISABLED (macbook pro) --- MIDI keyboard
    I have been away from home for about a month, without a charging block, so I have been charging my phone through USB. I recently tried plugging my MIDI keyboard into my laptop and received the 'USB devices disabled' notification. So far I have tried 2 things: leaving the computer off and disconnected from power overnight, and an SMC reset. No luck with either. However, I plugged in my audio interface into the USB port and it draws power just fine. I am wondering if a potential way around the keyboard problem would be to buy a keyboard that draws power from an AC adapter, instead of phantom, and only runs the MIDI information through USB. I don't want to spend the money on a new keyboard without being fairly confident it could work. Although if fixing whatever hardware is responsible for the issue would be cheaper than buying a new keyboard, I would rather do that. Thoughts/advice?

  2. #2
    USB DEVICES DISABLED (macbook pro) --- MIDI keyboard
    MacInWin's Avatar
    Member Since
    Jan 01, 2009
    Location
    Winchester, VA
    Posts
    6,787
    Your Mac's Specs
    MBP 15" Mid 2015, iPhone 11 Pro, an iMac, plus ATVs, AWatch, MacMini
    Rep Power
    27
    Try both another SMC reset and perhaps even a NVRAM reset. If the ports work for some things, they should work for all things. Charging your phone through USB should not render them disabled.

    BTW, Welcome to the forum. Take note of my sig and the threads listed there. The board may be disabled at any time, we don't know when it's going to happen.
    Jake

  3. #3
    Quote Originally Posted by MacInWin View Post
    Try both another SMC reset and perhaps even a NVRAM reset. If the ports work for some things, they should work for all things. Charging your phone through USB should not render them disabled.

    BTW, Welcome to the forum. Take note of my sig and the threads listed there. The board may be disabled at any time, we don't know when it's going to happen.
    Just tried the NVRAM reset and still no luck. The keyboard will receive power for 30 seconds or so and then shut off but during that period my audio software is completely unresponsive to any input from the keyboard. This was the case after 3 SMC resets as well

  4. #4
    USB DEVICES DISABLED (macbook pro) --- MIDI keyboard
    MacInWin's Avatar
    Member Since
    Jan 01, 2009
    Location
    Winchester, VA
    Posts
    6,787
    Your Mac's Specs
    MBP 15" Mid 2015, iPhone 11 Pro, an iMac, plus ATVs, AWatch, MacMini
    Rep Power
    27
    Did the phone exhibit any issues when you were using the MBP to charge it? I suspect that what you have is just a coincidental failure of the power supply for the USB ports that may or may not have started during the month of charging the phone. And you didn't say what brand of phone it was that you have. If it was non-iPhone, it may not have had smart charging circuits and made too large a demand on the USB ports.
    Jake

  5. #5
    USB DEVICES DISABLED (macbook pro) --- MIDI keyboard
    ferrarr's Avatar
    Member Since
    May 21, 2012
    Location
    Pawtucket, RI, US
    Posts
    6,822
    Your Mac's Specs
    L2014 Mac mini macOS 15, iPhone 8+ iOS 13, 12.9" iPad Pro 1 iPadOS 13,  Pencil 1
    Rep Power
    13
    You may be able to use the keyboard with a powered USB hub. An AC powered device will usually work better using USB ports.
    -- Bob --
    Please backup. Everything has a life cycle, unexpected and warning free. Nothing will last as long as you want it to.

  6. #6
    USB DEVICES DISABLED (macbook pro) --- MIDI keyboard
    chscag's Avatar
    Member Since
    Jan 23, 2008
    Location
    Keller, Texas
    Posts
    58,870
    Your Mac's Specs
    2017 27" iMac, 10.5" iPad Pro, iPhone 7+, iPhone 8, Numerous iPods, Mojave
    Rep Power
    53
    MIDI keyboards draw quite a bit of power and probably should not be plugged into the USB ports on a MacBook or MacBook Pro. You may be able to use it plugged into the USB ports on a late model iMac since those ports provide more power. Charging your iPhone thru the USB ports on your MacBook Pro should be OK. You may have damaged the USB power distribution for your MacBook Pro. Since you provided us with no specs for your MacBook Pro we can't really suggest a fix.

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