Troubleshooting USB devices on a digital audio workstation under Windows XP Matt Finley
Kingsmill Music
www.mattfinley.comOver the years, I have connected a great many USB devices to my computer. This includes not only audio-related sound devices (hardware synths, MIDI keyboards, Tranzport, iPod and other MP3 players, digital audio recorders, etc.), but also other peripherals like computer keyboards, wireless mice, graphics tablets, external hard drives, network interface cards, UPS power supplies, scanners, etc. Finally, I have a bunch of flash drives and a flash card reader.
I have learned three basic things about all this, and prepared a collection of resources to share. Here are three tips, listed in order from easiest to hardest:
First, it is important to plug a device into the same USB port each time. This avoids having the operating system load yet another driver. [What to do about this after it has occurred is explained below in the third tip.] Tip: on my computer, I ran a USB extension cable from one port in the back. Since I now plug every portable USB device into this cable, each device always gets loaded into the same port. A USB hub could serve the same purpose, except they have multiple USB ports and you should be careful to label them and use the same port for the same device each time. If your PC has multiple USB ports on the front panel, label them.
Second, it is important to be aware of the total power drain of USB devices. You can check the properties of each device and each port in the Windows Device Manager utility. Add up the total current draw for each device and make sure you haven’t connected more than the port can handle. Or, purchase a powered USB hub. If you exceed the current draw and you are lucky, one device will simply not work. If you are unlucky, devices will become intermittent, making diagnosis harder.
Third, and this is more complicated: it is important to be aware of the total number of USB drivers loaded on the system. In Windows XP, there appears to be a limit on the number of USB drivers and MIDI devices that can be handled, and if you exceed that limit, you may encounter devices that stop working or cannot be installed. This has happened to me several times. I have read that the limit is 10 for USB and 16 for MIDI, but I think it’s quite a bit higher for USB. Nevertheless, the following utilities have helped me to solve my problems by reviewing (non-destructive), disconnecting (non-destructive) or uninstalling (destructive) unused drivers.
Note that I cannot take any responsibility for any results you may obtain by using them, and always back up your computer and save your Registry before attempting any system driver repair work.• Windows has a built-in utility to see your unused USB devices, but it’s rather convoluted how to use it. It involves the Device Manager, which you probably know how to use, except that you must run it from DOS. Here are the steps:
To see unused devices (non-destructive):
1. Start, Run
2. cmd.exe
3. set devmgr_show_nonpresent_devices=1
4. devmgmt.msc
5. in Device Manager, View, Show Hidden Devices. Unused devices will have a greyed-out icon
• If you find there is an unused device driver for a device you have removed and no longer need, but Windows does not show its related program under Control Panel, Add/Remove Programs, backup your hard drive and Registry and then try these steps to make it visible:
To uninstall hidden components (preparing to be destructive):
1. Navigate to C:\Windows\
2. edit sysoc.inf
3. remove HIDE in wherever it appears as ,HIDE,
4. Go back to Add/Remove Programs, and see if the one you want can now be deleted
• A very good utility to view, disconnect or uninstall USB devices is a shareware program from
www.nirsoft.net called USBDeview. You can download it and view instructions at
http://www.nirsoft.net/utils/usb_devices_view.html• An easy way to see your USB and MIDI drivers in a Windows program is the uninstall driver utility from Korg, named UnInstDrv.exe Even if you do not have any Korg devices, it is worth it to download a driver and unzip it to get this utility. You do not have to install any Korg device, and you can delete the rest of the Korg files. Go to
http://www.korg.com/service/ then click on Downloads then Software. You do not need to select a particular Category or Product in the pull-down menus; just scroll down to C-520 88-key Concert Piano, and select PC and download the driver (2.8 MB). Unzip it and execute it. A Typical installation will be fine. This will install files into Program Files\KORG\KORG USB MIDI Driver. One of the files in that folder will be UnInstDrv.exe. Copy/save that file elsewhere, and then you can uninstall the Korg driver from Add/Remove Programs. Note that there is also a 64bit version of the utility, a different file.
UnInstDrv.exe will show you the USB and MIDI slots and allow you to remove the unnecessary ones if you click the Option... button and uncheck Korg Only first. Obviously, this is a destructive utility, so perform your backup procedures first. I found several entries marked “Corrupted” and deleted them, and my system runs smoother. The error that prompted me to use this utility was a message in Device manager that said, "Driver is installed but not functioning properly". Apparently I exceeded the limit (whatever it is) of allowed USB drivers. Once I deleted the corrupted entries and reinstalled the new device, it worked.
___________________________________________________________________________________________________________________________________
Corrections to the information in this document are most welcome.
Last revised: April 21, 2008