Troubleshooting Class Compliant USB Devices

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other class compliant usb icon3Most USB audio and MIDI computer peripherals are "Class Compliant" devices. This means that to communicate with the computer, they use drivers that are built right into the host computer’s operating system. These drivers are written by Microsoft (or Apple for Mac OS X), and come pre-installed on all computers. In some cases, these devices may have trouble connecting due to software settings, changes to the operating system, out-of-date system drivers and even hardware problems.

This guide discusses some common troubleshooting steps to determine the cause of these issues and provide some potential solutions.




What does 'Class Compliant' mean?

A class compliant device is one that does not require extra drivers to connect to your Windows or Mac computer, or to your iPad. Class compliant devices use drivers which are built into the host (i.e. the computer or the iPad) operating system.

To find out if your USB audio or MIDI device is class compliant, check the manufacturer's web page.* If it connects automatically to any computer without requiring you to install drivers from a website or a disk, it is probably class compliant.

*Please Note: Some devices may be listed as class-compliant even though they come with additional drivers. The drivers add additional support for more complicated audio/MIDI functions (i.e. reduced latency, mapping support, sysex transfers etc.). Check the product page or the driver download page for an available driver.

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Potential Symptoms and Potential Causes

Some typical problems with a class-compliant USB device include:

  • Device will not power on
  • Operating system error after the device is plugged in. This is usually only associated with Windows and the error may report something like the "Device/Driver could not be installed," "Driver could not be found," or "USB device not recognized."
  • Device is not recognized in software
  • Device is recognized but does not respond
  • Device connects and works briefly but disconnects

Remember that these devices are built to use drivers that come pre-installed in your operating system. Most potential causes will be because these drivers are not installed, were not updated properly, are in conflict with other devices or drivers,  or have become corrupted. Other potential causes include:

  • A bad USB cable or port
  • Poor communication, typically due to the use of a USB hub, long or extended USB cables, or having too many USB devices plugged in.
  • Missed settings or steps with software or hardware setup

The first steps when you encounter a device not connecting properly should always be to try different USB cables, different USB ports and even a different computer. You will also want to disconnect other USB peripherals and avoid USB hubs (though it's often useful to take note of the response with and without a hub involved). About 95% of these inquiries can be resolved by doing so and can help confirm that the device itself is at least working properly. 

With this in mind, the following sections will go through some steps to test the response of your device and provide some potential solutions.

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Quick Test

When you're frustrated with not being able to get up and running, or if you're thinking you might  have a defective product, this 10-second is-it-broken test can restore the confidence necessary to continue working with the product and to complete any needed software setup or authorization process.

An M-Audio Keystation Mini 32 will be used as an example for these tests. Please use any reference to the Keystation Mini 32 as a reference to your own device.

Windows XP to Windows 10

  1. Connect your USB device and open the Device Manager. You can find this in your Control Panel. If sorted by category, click on Hardware and Sound to find the Device Manager.

    USB Device

  2. Double-click on the Sound, Video and Game Controllers category and you should find your device:

    USB connect

    If your device appears similar to the image above, this will indicate that it's connected and communicating properly. If you are still having trouble with response from the device, please refer to the Further Troubleshooting section or contact Technical Support for further assistance.

  3. If the product appears with a yellow triangle or other icon next to it, and/or appears in a different category in Device Manager, this may just indicate that the drivers are not installed correctly or are out of date. Remember that these are windows drivers and are not specific to your device. For more information on resolving this, see Step 2 in the Further Troubleshooting section of this guide.

    USB connecting

  4. If the product does NOT appear according to the tests above, the device may just be labeled differently in the device manager or it may indicate a problem with the device. An easy way to test this is to watch the Device Manager while unplugging the device. If the Device Manager flashes, that will indicate that the computer does see your device and may just be putting it in another category or labeling it something different. Plug the device back in and watch the Device Manager again to see what pops up. That will be your device.

    Often times the system may label something it doesn't recognize as just "USB Audio Device." This is another indication that drivers may not be installed or updated correctly as discussed in Step 3

    If the Device Manager does not flash at all, this means that your product is not recognized by the computer and could indicate a problem with the device. This is a good opportunity to try different USB cables, different ports and confirm with a different computer. If this appears to be the case, contact Technical Support for further assistance.

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Mac OS X

  1. Disconnect your USB device, count to 5 and then plug it back in.

  2. In the upper-left of the screen, click the Apple Menu, and select About This Mac.

    USB about

  3. In the window that appears, click on System Report. A new window will open.

    USB system

  4. A System Report window will be displayed.  On the left-hand side of the window, under Hardware, select USB.


  5. On the right, you will see all of your available USB buses and their connected devices. You can expand each bus by clicking on the arrow next to it. If your USB device is connected, you should see it displayed under one of these:

    USB hardware

  6. If you do not see your device listed here, disconnect it, and select File > Refresh Information. This will make the computer rescan the ports.

    mac quick test 5

  7. Connect the keyboard to the computer again, and select Refresh Information a second time. Your device should hopefully appear.

If the device does pass the test above and appears in the System Report, it is not defective, and the difficulty is caused by misconfigured software settings or options.  Carefully follow the setup instructions for the software you are using, or navigate to the Further Troubleshooting section for additional tests and troubleshooting.

If the device does NOT pass the test above, and does NOT appear in the System Report, this may indicate that the device is defective. At this point, you will want to test different USB cables and USB ports. It may also be a good idea to run the same test with a different computer. If you continue to run into trouble, contact our Technical Support team for further assistance.

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Further Troubleshooting

  1. Using a MIDI Monitor to Test Your Device

    If your device passes the Quick Test above but you still don't see any response from it (does not show up in your software, will not trigger your virtual instrument, etc.), you can use a MIDI Monitor to confirm if it's still communicating correctly with the computer. If the keyboard or device is responding differently than expected, this can help confirm exactly what data the device is sending to the computer.
  2. USB 3.0 Ports and USB 2.0 Devices

    It may be useful to check if your computer has USB 3.0 ports, which can cause problems if not updated correctly. For example, if your device passes the test on one computer and not another, this may be the reason. This guide will walk you through checking your UBS 3.0 ports and chipset drivers.
  3. Mac OS X - Problems With MIDI Devices After an Update

    This guide walks through deleting MIDI drivers on a Mac. This may be necessary if issues appear only after updating your operating system, or may be useful to determine if a driver was installed correctly or not.
  4. Mac OS X - How to Re-Configure Your MIDI Studio

    This guide demonstrates how to create a new configuration for your MIDI setup in Mac OS X. This may be helpful if your device is not recognized by your software and you have recently updated your OS or changed the connected devices.

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Prescription Resources

The three resources below are to be considered prescription medicine... only to be used to remedy a specific symptom. These are not general maintenance tools.  It is not recommended that you use these resources unless you are confident you are affected by the specific scenarios that cover them above. Use these files at your own risk.  If you are uncertain whether or how you should use the resources below, contact Technical Support.

  • Logitech Camera Driver Conflict – If you’ve ever connected one of these web-cams to your Windows PC you’ll have trouble using USB audio or MIDI devices. This will typically affect Windows XP and Windows Vista computers. Please download the necessary files and instructions from this link - Logitech Camera Fix (zip)

  • Missing or corrupted Windows or Mac OS X files – These class-compliant products use drivers built in to the Windows and Mac operating systems. If these files are missing or corrupted, the product won’t function as expected. Of the potential causes for difficulty described in this article, this is the least likely.  All other potential causes should be ruled out first.  Download the necessary files and instructions here - Win 7, Vista, and XP - USB Audio Codec Drivers (zip)

  • Computer Peripheral Testing - Ruling out software setup errors versus hardware failure can be difficult.  This archive includes resources and instructions that can be used to test any class-compliant USB Audio or MIDI computer peripheral in about 2 minutes. The guide was developed to shorten evaluation time for repair depots, service centers, and is not intended as a self-support tool for general public.  Please check with Technical Support to find out if this is necessary before continuing. Download the necessary files and instructions here - Computer Peripheral Testing (zip)

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Further Technical Support

It's impossible to cover all of the possibilities of USB troubleshooting in a single guide but this should act as jumping off point. The suggestions above should at least help you quickly determine that a product is functional, and to help you overcome common setup obstacles such as poor USB communication or out-of-date drivers. If you require further assistance with product setup or have determined that the product is NOT functioning correctly, contact the Technical Support team or refer to some of the related articles below:

Technical Support:

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