Mac displays "USB Accessories Disabled" error with self-powered USB keyboard

The “USB Accessories Disabled” message can appear even though the Casio CDP-220R has its own mains power supply. 

Apple recommends disconnecting the accessory, reconnecting it, trying another port, and connecting it directly to the Mac rather than through a hub.

You have already tried different ports and cables and confirmed that no hub is involved.

The next step is to determine at which point the connection is failing: USB detection, MIDI detection, or communication with Logic Pro or GarageBand.

First, disconnect the USB cable from both the Mac and the Casio. Turn the Casio off, then turn it back on before starting the music software, as recommended in the CDP-220R manual. 

Reconnect the USB cable directly to the Mac. (CASIO Official Website)

Then open System Information and select USB under Hardware. 

Check whether the Casio, or a device identified as “CASIO USB-MIDI,” appears.

If it does not appear in System Information, macOS is not currently listing the keyboard as a connected USB device. 

Since you have already tested different ports and cables and the same result occurs on two Macs, that information would be useful to provide to Casio for further troubleshooting.

If the keyboard does appear in System Information, open Audio MIDI Setup, choose Window > Show MIDI Studio, and check whether the keyboard appears there. 

Apple states that USB MIDI devices are normally detected automatically. 

If the device is not shown, click the Rescan MIDI button and confirm that the keyboard is connected and turned on. (Apple Support)

If the Casio appears in MIDI Studio, test the MIDI connection rather than proceeding immediately to Logic Pro or GarageBand. 

Select the device, click Test MIDI Setup, and play notes on the Casio.

Apple explains that MIDI activity can be checked in MIDI Studio during this test. (Apple Support)

This gives three distinct results:

If the Casio does not appear in System Information, the problem is occurring before macOS has listed the keyboard as a USB device.

If it appears in System Information but not in Audio MIDI Setup, use Rescan MIDI and repeat the connection test.

If it appears in Audio MIDI Setup and responds during the MIDI test, the USB and MIDI connection is working, and the next step would be to check the device selection and MIDI settings in Logic Pro or GarageBand.

The Terminal command stopped the “USB Accessories Disabled” message, but it did not make the keyboard available to Logic Pro or GarageBand. 

Therefore, stopping the message did not restore MIDI communication in this case.

Casio's USB-MIDI compatibility information lists macOS 15 as compatible and indicates that a special driver is not required. 

The CDP-220R manual also identifies “CASIO USB-MIDI” as the device used with Mac music software.

For that reason, installing the Windows driver would not appear relevant to this Mac setup. (CASIO Official Website)

If the CDP-220R still does not appear in System Information on either Mac after these tests, I would give Casio the following information: the keyboard triggers the “USB Accessories Disabled” message and does not appear in macOS System Information on either of two Macs, despite testing different ports and USB cables. That should give Casio a clearer basis for advising on further troubleshooting.

Apple's USB troubleshooting information:

If you see USB Devices Disabled on your Mac

Apple's MIDI detection instructions:

If a connected MIDI device isn’t shown in Audio MIDI Setup on Mac

Apple's MIDI testing instructions:

Test your MIDI setup

Casio's USB-MIDI compatibility information:

Casio USB-MIDI compatibility information

The CDP-220R manual:

Casio CDP-220R manual

randomname47 wrote:

Yesterday I got the system message "USB Accessories Disabled - Unplug the accessory using too much power to re-enable USB devices."

So this occurred in a configuration which has worked in the past, then suddenly stopped working with no changes to your setup? That would strongly implicate either the keyboard or its power supply, I am hypothesizing it is the power supply, see below for my reasoning.

I have no idea how to test the power output of the A/C adaptor. Anyway, as this message appears when the keyboard isn't connected to a power source at all, I'm not sure that's where the problem lies.

I've tried various cables and ports on both machines. I have now updated to OS 15.7.9 on both.

This happens on both my computers, a 2022 Mac Studio running OS 15.7.5 Sequoia, and a 2018 Mac Book Pro running OS 15.5 Sequoia.

I am pretty sure that your keyboard's separate power supply no longer works properly. (It is also possible the keyboard itself has failed but I would start with the power supply, see below.)

• What you experience happens on two different Mac models
• You see the error when you disconnect the keyboard power source. Which means you see the same problem with no power source and also when you plug the power source in. Which is consistent with the power source providing either no power or not enough power, which then means the keyboard draws on Mac power through the USB, prompting the error notification. It needs too much power, the Mac USB port cannot provide enough.
• For instance, I THINK your keyboard's power supply provides 18W. However Mac ports can provide typically 4.5W, 7.5W (USB), or up to 15W (Thunderbolt/USB 4). So if the keyboard tries to get its 18W the Mac cannot meet that need and returns an error. This is my guess about what is happening.

Since the keyboard is much costlier than a new power supply for it, I would (after trying different power outlets just to rule out that unlikely possibility) probably first obtain a new power supply (I see several offered online) and try that first. Or, is there a self test you can do with the keyboard without having to connect it to a computer?

Also, carefully examine the power supply and its cord for any fraying or signs of wear/tear. That said, unless you move this device around a lot, wear/tear seems unlikely.

Hopefully a new power supply will resolve this, that would be a ~ $20 (US) cost, versus hundreds of $ (US) for a keyboard, and I don't think this model is manufactured anymore. It's a very feature-rich music keyboard, I have to say it looks impressive! Power supplies are often the culprit in cases like this because they are relatively inexpensive and thus cheaply made and they have the active components that are most vulnerable to failure.

The message “USB Accessories Disabled – Unplug the accessory using too much power to re-enable USB devices” is generated when macOS detects a USB power-related condition. 

The fact that your Casio CDP-220R has its own mains power does not necessarily prevent this message, because the keyboard is still electrically connected to the Mac through USB.

Apple recommends disconnecting and reconnecting the device, trying a different USB port, and connecting the device directly to the Mac rather than through a hub. Apple: If you see USB Devices Disabled on your Mac

Since the same keyboard produces the message on two different Macs, try a different known-working USB cable and connect the keyboard directly to each Mac. 

This does not establish that the existing cable is faulty; it simply tests whether changing it affects the result.

You can also fully disconnect the keyboard before trying again: shut down the Mac, disconnect the USB cable, turn off and unplug the Casio from mains power for a few minutes, then reconnect everything and restart the Mac.

After reconnecting, check whether macOS detects the keyboard.

Hold the Option key, choose Apple menu  >> System Information, then look under Hardware >> USB. 

Apple explains how System Information can be used to view connected hardware here: Apple: Use the ports on your Mac and check connected devices

If the Casio appears, copy and paste its complete USB entry here. The device name, Vendor ID, Product ID, connection speed, and any power or current information may help clarify what macOS is detecting.

At this point, the cause cannot be identified from the available information. Testing another cable and checking the keyboard's USB entry in System Information should provide more information before making changes to Logic Pro or macOS.

randomname47 wrote:

Thank you. I have no idea how to test the power output of the A/C adaptor.

You need to test or have someone test the Casio keyboards power adapter using a multi-meter.

Anyway, as this message appears when the keyboard isn't connected to a power source at all, I'm not sure that's where the problem lies.

That Casio keyboard must have that external power source connected in order for it to work.

Does the Casio keyboard play from its built-in speakers or headphones when it is not connected to a computer...?

I've tried various cables and ports on both machines. I have now updated to OS 15.7.9 on both.

If the Casio keyboard does not play from its built-it speakers or headphones, then there is something wrong with the keyboard or its power adapter.

I'm extremely reluctant to go to Tahoe. No new version since OS X has given me anything I wanted, only made things I already did more complicated and difficult, and in some cases, impossible. There are still basic inconsistencies with the ultra-primitive (Multi)Finder that haven't been touched since System 7, when multi-processing was relatively new and exciting! So I would only upgrade my OS when some piece of software I need to use refuses to run. I really don't relish having to learn loads of stuff which is no use to me at all, just to get the machine working my way, and to get this keyboard working. Especially as I'm not convinced that it will. But if I have to do that, if I really have to, I will. But if I have to do that, AND buy a new keyboard, I shall be extremely p***ed off. I need to use it now, and I have no money for a new one.

The Mac or the macOS version will not make any difference, if the Casio keyboard is not working properly.

Still heard nothing back from Casio, as expected.

That is where you need to go to sort out any problems with the Casio keyboard.

The other option, take the keyboard to the local music store that sells and repairs Casio keyboards.

1) Test a different USB cable between the Casio Keyboard and your Mac's.

Test the Casio's power brick adapter to make sure that it is outputting 12V.

http://arch.casio-intl.com/asia-mea/en/emi/contemporary/cdp220r/spec/

2) The macOS versions of Sequoia on both of your Mac's needs to be Updated.

What's new in the updates for macOS Sequoia 15 - Apple Support

and/or optionally, Upgrade the 2022 M1 Mac Studio to Tahoe 26.

What's new in the updates for macOS Tahoe 26 - Apple Support

randomname47 wrote:

I don't get how this can be a power supply problem, as it happens even before the keyboard is connected to a power source, let alone switched on.

I guess my logic was that when you connect the keyboard to the Mac without the keyboard's power supply, the Mac gives you a message that it detected too much power draw from the USB port. You get the same message when the power supply is connected, e.g. connecting the power supply results in the same message from the Mac as you get without the power supply. Hence I thought maybe you are getting no power (or inadequate power) when the power supply is disconnected as well as when it is connected, e.g. connecting the power supply gives the same error as when there is no external power coming to the keyboard (power supply disconnected).

But I can't even see these devices, I'm just reading about them, and I could be totally off base in my interpretation. I do agree it could well be simply the USB connection is faulty. That would likely implicate the keyboard USB port because (a) it happens with more than one Mac, and (b) you tried different cables. It seems the only thing left to be the cause here is the USB circuitry of the keyboard, maybe?

Surely the problem is either with the keyboard itself, or settings on the computers that need to be changed, or maybe both?

Based on my thoughts above, I am suspecting the keyboard USB circuitry now, because you indicated that the power supply provides enough power for the keyboard to work as an electric piano when no computer is connected.

As for computer settings, does it make sense to you that both computers share the problem? Hence also my question about whether this all worked in the past (with both computers) and then suddenly stopped working for no identifiable reason? Did anything in the setup change? On both computers or elsewhere?

Perhaps the USB connector on the keyboard is damaged, but I don't know how to check that out. The keyboard itself, sans USB, works fine. It's a digital piano, and I can still use it as such.

Based on your knowledge of this keyboard, when there is a USB connection to the Mac, what is the purpose of that connection? Is it only for a data connection, or is the Mac supposed to provide some amount of power?

If it is supposed to only be a data connection, then it seems that the keyboard is drawing power through that USB link that it should not be. Another circumstantial bit of evidence that the keyboard itself is faulty USB-wise.

randomname47 wrote:

The keyboard works fine when plugged into the mains and not connected to the computer via USB. It plays okay, through its speakers, and through headphones, and AFAICT, all the various controls work okay. The problem is definitely with the USB connection.

If possible, test the Casio keyboard plugged into a different Mac or into a Windows PC.

Also keep in mind, that the keyboard needs to be plugged into both the mains via the supplied adapter and into the computer via a USB cable in order for it to work.

Casio seem to be suggesting that the keyboard is broken, and I need to buy a new one (without asking very many questions), but then they would say that, wouldn't they!

That is true of most all hardware retailers.

den.thed wrote:

randomname47 wrote:

Thank you. I have no idea how to test the power output of the A/C adaptor.

You need to test or have someone test the Casio keyboards power adapter using a multi-meter.

Anyway, as this message appears when the keyboard isn't connected to a power source at all, I'm not sure that's where the problem lies.

That Casio keyboard must have that external power source connected in order for it to work.

Does the Casio keyboard play from its built-in speakers or headphones when it is not connected to a computer...?

I've tried various cables and ports on both machines. I have now updated to OS 15.7.9 on both.

If the Casio keyboard does not play from its built-it speakers or headphones, then there is something wrong with the keyboard or its power adapter.

I'm extremely reluctant to go to Tahoe. No new version since OS X has given me anything I wanted, only made things I already did more complicated and difficult, and in some cases, impossible. There are still basic inconsistencies with the ultra-primitive (Multi)Finder that haven't been touched since System 7, when multi-processing was relatively new and exciting! So I would only upgrade my OS when some piece of software I need to use refuses to run. I really don't relish having to learn loads of stuff which is no use to me at all, just to get the machine working my way, and to get this keyboard working. Especially as I'm not convinced that it will. But if I have to do that, if I really have to, I will. But if I have to do that, AND buy a new keyboard, I shall be extremely p***ed off. I need to use it now, and I have no money for a new one.

The Mac or the macOS version will not make any difference, if the Casio keyboard is not working properly.

Still heard nothing back from Casio, as expected.

That is where you need to go to sort out any problems with the Casio keyboard.

The other option, take the keyboard to the local music store that sells and repairs Casio keyboards.

+ 1 my friend