UMBus Root Bus Enumerator - Unknown Device  

Hi there,

I tried to install a wireless Logitech keyboard/mouse combination. The keyboard works fine, the mouse doesn't. The device manager shows the "UMBus Root Bus Enumerator" as unknown device. I researched in some forums and found this: "sc config umbus start= demand". But it doesn't work.

In this forum I found an older threat with this post:
Go to Device Manager > Action > Add legacy hardware > Next > Install the hardware that I manually select from a list > Next > click on "System Devices" > Next > then under "Manufacturer" click on "Microsoft" then under "Model" click on "UMBus Root Bus Enumerator" > Next > Next

But when I want to install legacy hardware, the software asks for a storage device with the drivers. The installation DVD doesn't work. What to do?

Any help is appreciated.
Natikabu

Check if these 3 files exist

1. C:\Windows\inf\umbus.inf
2. C:\Windows\inf\umbus.pnf
3. C:\Windows\System32\drivers\umbus.sys

Yes, these files exist in the correct folders.

Look under System Devices. Is UMBus Enumerator listed? Missing? There with an error (yellow icon)

Reboot your machine. Navigate to folder C:\Windows\inf. You should find a file named either setupapi.dev or setupap.dev.log. In either case, zip it and upload to next post

Yes, both devices are listed. Attached you find both files setup files.

This is the content of DevicePath:
%SystemRoot%\inf;C:\Program Files\Samsung\USB Drivers\01_Simmental;C:\Program Files\Samsung\USB Drivers\02_Siberian;C:\Program Files\Samsung\USB Drivers\03_Swallowtail;C:\Program Files\Samsung\USB Drivers\04_semseyite;C:\Program Files\Samsung\USB Drivers\05_Sloan;C:\Program Files\Samsung\USB Drivers\06_Spencer;C:\Program Files\Samsung\USB Drivers\07_Schorl;C:\Program Files\Samsung\USB Drivers\08_EMPChipset;C:\Program Files\Samsung\USB Drivers\09_Hsp;C:\Program Files\Samsung\USB Drivers\11_HSP_Plus_Default;C:\Program Files\Samsung\USB Drivers\16_Shrewsbury;C:\Program Files\Samsung\USB Drivers\17_EMP_Chipset2;C:\Program Files\Samsung\USB Drivers\18_Zinia_Serial_Driver;C:\Program Files\Samsung\USB Drivers\19_VIA_driver;C:\Program Files\Samsung\USB Drivers\20_NXP_Driver;C:\Program Files\Samsung\USB Drivers\21_Searsburg;C:\Program Files\Samsung\USB Drivers\22_WiBro_WiMAX;C:\Program Files\Samsung\USB Drivers\24_flashusbdriver;C:\Program Files\Samsung\USB Drivers\25_escape

I deleted everything except the "%SystemRoot%\inf" and rebooted the system, but nothing changed. I remember, that the problem began after some software installation, but I don't remember what it was.

Now the problem ist solved. I tried again the Update Driver option in the Device Manager and manually set the path to Windows/inf. The driver was updated and everything works fine. All new USB devices are found now.

Thanks a lot for your support. It helped me to understand the structures of Windows a bit deeper.

Hi Natikabu

You're most welcome. Glad i was able to help. (And thanks for the rep!)

I'm glad you got it to work but one last thing puzzles me: Your data indicates %systemroot%\inf is, in fact, in DevicePath

So, please verify this: Open File Explorer, type %systemroot% as the file path, hit Enter.

• If Explorer takes you to folder C:\Windows, %systemroot% is OK and i guess this is just another Windows mystery!
• But if you're NOT taken to C:\Windows, then the value of systemroot is corrupt and need be fixed

Good morning ComputerGeek,

%systemroot% takes me to C:\Windows as it should. It seems we're indeed tapping around in the mysterious realms of Microsoft.

Thanks again and all the best
Natikabu