I recently bought a Roku Express for my TV.
It works fine.

However, I have been unable to use it to mirror the display on my Win 10 Desktop to the TV.

I've checked that mirroring is enabled in the 'settings' menu on the Roku.

'netsh wlan show driver' in a command window on the PC shows:-
    Wireless Display Supported: Yes (Graphics Driver: Yes, Wi-Fi Driver: Yes)
So the PC (graphics card & drivers) appear to support Miracast.

My graphics card is a Geforce GTX-960.
I tried 'dxdiag' from a command window. This shows:-

                 Miracast: Available, with HDCP
            Miracast: Not Supported by Graphics driver

However, another forum suggests Miracast should work on a NVIDIA GeForce GTX 960:-

https://forums.evga.com/EVGA-GeForce-GTX-960-Miracast-Not-Supported-by-Graphics-driver-m2741883.aspx

In my case, the PC is normally connected to my wireless router using a gigabit Ethernet cable.
Having read that Miracast only works over WiFi, I ensured that the wireless card in the PC is also enabled.
I even tried disabling the wired ethernet connection to the router and using WiFi instead.
It made no difference.
Whatever I try, the Roku device does not show up.

Has anyone managed to get this to work?

What's the exact model of your Roku Express? I think the older model didn't have screen mirroring. Also, is it a Express+ connected via analog?

I think "Miracast: Not Supported by Graphics driver" says it all. Regardless of what the forums might say, your computer is reporting it isn't supported. And the computer has to be the one that says it will work. I just checked my desktop, which doesn't have a WiFi card in it, and I get a simple Not supported message. And in my Devices list none of my Roku devices appear. One TV, one Blu Ray player and my Nvidia Shield all appear, but nothing else. 

I'm not yet convinced the problem is connected with the graphics driver.

This post in the NVIDIA forum about the GTX-960 suggests the information from 'dxdiag' is either incorrect or misleading:-
https://www.nvidia.com/en-us/geforce/fo ... cs-driver/

This post in a Microsoft forum suggests it's more likely to be the Wireless adapter card that may be the problem:-
https://answers.microsoft.com/en-us/win ... d22?page=1

Clearly the Roku Express device itself supports Miracast because mirroring appears in the setup menu.

I'm still investigating.

My wireless adapter card is an Intel 8260.

According to the information below, it does support Miracast:-
https://www.wi-fi.org/product-finder-re ... mpanies=56

I tried updating the drivers for both the GTX-960 graphics card and the Wireless card.
Still no joy.

I found this:-
https://support.roku.com/en-gb/article/ ... ws-device-

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Does my Roku device support screen mirroring?
Most current generation Roku streaming players and Roku TVs support screen mirroring with notable exceptions listed below. To find the model of your Roku device, go to Settings > System > About.

• Roku Express: Screen mirroring is only supported on model 3900 (introduced in 2017), and not on model 3700.
• Roku Express+: Screen mirroring is only supported on model 3910 (introduced in 2017), and not on model 3710. With model 3910, screen mirroring is only supported on the HDMI output, and not on the composite, or A/V output.

You can use the Roku device comparison chart to determine the current products that support screen mirroring for Android and Windows devices.
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My device is a Roku Express model 3900, so mirroring should be supported.

Mirroring from a Windows PC has always been mostly a miss.  Mirroring from an Android where Google hasn't disabled Mirracast has always been somewhat of a hit.  Neither of them look particularly good on the screen.

twiceover wrote:

Mirroring from a Windows PC has always been mostly a miss.  Mirroring from an Android where Google hasn't disabled Mirracast has always been somewhat of a hit.  Neither of them look particularly good on the screen.

Stop wasting time on this. You will never get it to work correctly. Spend $35 on a Chromecast.

I also heard Windows 10 May Update breaks something with this as well. I've had good luck getting this to work with Integrated Graphics on laptops, Alienware laptops and an ASUS tablet. One thing to make sure is that the Roku and the Wi-Fi on the PC are on the same GHz band.

scottypie1234 wrote:

twiceover wrote:

Mirroring from a Windows PC has always been mostly a miss.  Mirroring from an Android where Google hasn't disabled Mirracast has always been somewhat of a hit.  Neither of them look particularly good on the screen.

Stop wasting time on this. You will never get it to work correctly. Spend $35 on a Chromecast.

I have been considering this option. However, am I right in thinking that, with Chromecast, you are limited to mirroring content from a Google Chrome browser? One reason I chose a Roku streamer is that I don't have a smart phone or a tablet, so a Chromecast device would be of limited use.
In any case I have not yet found a good reason why Miracast should not work with Win 10 on my hardware.
I did try to get Miracast to work using an old Acer laptop running Win 7. Win 7 does not natively support Miracast, but you can install the (now unsupported) Intel WiDi driver software. Unfortunately the WiDi installer quit after it indicated it was not compatible with the hardware (probably the Wireless adapter).