SOLVED: DisplayLink drivers weren't working after Win8.1 upgrade
 

In this case I believe the latest 7.4 M2 drivers were *not* installed before the upgrade to Windows 8.1. At any rate we figured it should still be possible. This was done on a Microsoft Surface Pro and a Targus APC7xx dock (tried two different docks as well as a 16" AOC USB monitor).

The notification sound would work but a number of Targus devices showed up with a yellow bang under unknown/other and no displays would work. Not even an external USB display (separate from Targus dock) would work.

We tried unplugging all USB DisplayLink devices, uninstall driver software, reboot computer, run cleaner utility, reboot, install driver software, reboot, power cycle dock, then plug in dock and same thing.

On top of it, Windows Update is claiming there's an updated driver and it fails to install. Tried downloading it manually from the Windows Catalog, still failed to install.

In the end a combination of things worked and here are the things I think that really effected the changes and it required me having a system with DisplayLink working using the 7.4 M2 drivers... not sure if it requires Windows 8.1 but that's what I had to work with:

1. Run Autoruns (Sysinternals) and look in the Drivers tab for missing DisplayLink driver files. I copied these over from another Surface Pro that works with the dock and Windows 8.1 (DisplayLinkUSBxxxx.sys in C:\Windows\System32\Drivers as well as dl****.sys files).

2. Copy these folders from the working system to the non-working system, located in the C:\Windows\System32\DriverStore\FileRepository folder:

displaylinkusb.inf*** folder
dlcdccm6.inf*** folder
dlusbaudio.inf*** folder

3. Reboot computer and plug in dock. If still no proper devices showing up go to the Targus USB3.0 dock device (or similar if you have another DisplayLink device), right-click and update drivers. ** CHOOSE to browse your computer for drivers.

4. Navigate to C:\Windows\System32\DriverStore\FileRepository and make sure "Include subfolders" is checked. In my case, it actually found the right driver this time.

5. Repeat steps 3-4 for any remaining devices and reboot. At this point all devices worked for me.

Hope that helps someone!

Other things I had tried before all this that I don't think had any effect but might help you:

I removed all hidden DisplayLink devices from the Device Manager. Not just hidden ones but all "non-present" devices that related to my DisplayLink device. How to do this:
1. Click Start, click Run, type cmd.exe, and then press ENTER.
2. Type set devmgr_show_nonpresent_devices=1, and then press ENTER.
3. Type Start DEVMGMT.MSC, and then press ENTER.
4. Click View, and then click Show Hidden Devices.

Now you'll see not only hidden devices but "non-present" ones as well. Uninstall each DisplayLink device you find. Then do a reboot.

One last thing… I used a USB 3.0 hub near the end of my testing and when plugging in the USB monitor (not dock) as a test that was the first time it worked. Unfortunately I had already copied over some of the folders above so I'm not sure if it was the folder copy or plugging the monitor into the USB 3.0 dock that triggered things starting to work.

WIndows 8.1 device not detected
 

Do you happen to have those drivers/inf files ?
I do not have a working device and since I upgraded to Windows 8.1 the device is not detected. I have tried everything.

I'll try attaching them here in a ZIP file. Inside the ZIP file you'll find the 3 folders.

Thanks for the quick response. I will try it and let you know.

I tried that and still do not see any drivers loaded via sysinternals autoruns or devmgr.msc.
In step #1 above, do you have any displaylink drivers under C:\Windows\System32\Drivers ?

Yes, there are 5 drivers listed, even when I don't have the DisplayLink device connected. Bear in mind I have two different devices, a USB monitor and the Targus USB 3.0 dock so you might not see all these drivers listed. See attached screenshot.

Also remember to try connecting a USB 3.0 or even a USB 2.0 hub to your computer and temporarily connect your DisplayLink device to that. Seems that at some point it needs to be connected to a completely different USB port/controller to give itself a kick in the head and reset things.

There really needs to be a RESET button/switch on these devices that clears out all its cached/internal data.

I do not have any of those files/drivers under that specific dir.
Can you pls attach those also ?

Absolutely. See attached ZIP from files in the C:\Windows\System32\Drivers folder.

Thanks for doing that. That still did not help me.
Not sure where to go now.

Can anyone help direct me where to go next pls ?