To troubleshoot USB devices that may not function correctly using Citrix Generic USB Redirection. Such as devices that work correctly when redirected using  Single User Desktop OS VDAs, but may not work correctly in Multiuser Server VDAs. A useful troubleshooting step is to test redirecting the device using RDP Remote FX USB, if the device shows the same behavior then it may be the device driver that is causing the problem as some devices drivers are not designed to be used in a multiuser environment.

Instructions

To enable RemoteFX USB redirection, we need to make some temporary changes to the endpoint and the VDA. This can be achieved using the local policy editor (gpedit.msc) Note: the VDA software does not need to be installed, but it will not affect the test if it is.

To configure the client machine (endpoint) 

1. Start Local policy editor - gpedit.msc
2. Browse to: In Group Policy, navigate to Computer Configuration -> Administrative Templates -> Windows Components -> Remote Desktop Services -> Remote Desktop Connection Client-> RemoteFX USB Device Redirection,
3. edit “Allow RDP redirection of other supported RemoteFX USB devices from this computer.”
4. Enable the policy, and specify Administrators and Users, then click OK
5. Restart the Endpoint computer for the changes to take effect. The feature will not work until you restart.

To configure the Server (VDA) 

1. Start Local policy editor - gpedit.msc
2. Browse to: Computer Configuration -> Administrative Templates -> Windows Components -> Remote Desktop Services -> Remote Desktop Session Host -> Device and Resource Redirection
3. Edit “Do not allow supported Plug and Play device redirection” and set it to Disabled, then click OK
4. Close local group policy editor

To Redirect the Device Using RDP Remote FX USB Redirection

1. On the Endpoint, start RDP client – mstsc.exe
2. Add the hostname or IP address of the VDA
3. Click “show Options” if not visible
4. Select the “Local resources” Tab
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5. Uncheck "Printers"
6. click “More…”
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7. Uncheck "Drives"
8. Expand “Other Supported RemoteFX USB Devices”
9. Select the USB device under "Other supported RemoteFX USB devices" (in the above example case this is a "Jabra Link 370", but you should select the affected USB device here) 
10. Click OK and then Connect, to connect to the server using RDP.

To confirm the device is connected using Remote FX USB redirection

1. Inside the session open device manager (devmgmt.msc)
2. Go to the View menu and again select “View devices by connection”
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3. Locate and expand "UMBus Root Bus Enumerator"
4. Expand all of the "UMBus Enumerator" subtrees until you locate the “Remote Desktop USB hub” 
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5. All devices redirected by RemoteFX USB will be under the “Remote Desktop USB hub” (if the device is not present under here, then the device is not redirected via Remote FX USB redirection)
6. Test if you see the same issue with RemoteFX USB redirection

Additional information about redirecting devices using RemoteFX USB redirection can be found here: https://learn.microsoft.com/en-us/troubleshoot/windows-client/remote/usb-devices-unavailable-remotefx-usb-redirection

The Citrix USB Diagnostics tool should be used before attempting to test with RemoteFX USB redirection: https://docs.citrix.com/en-us/citrix-virtual-apps-desktops/devices/usb-devices/usb-diagnostics-tool.html