Issues with Miracast since October Patch (Wrong

Question

Issues with Miracast since October Patch (Wrong

Alexander Fisher 20

Hi All,

On a fleet of various devices (25H2 and 26H2). We are getting constant issues with the correct resolution casting to our miracast devices (teams rooms, screen beams etc).

When duplicating the screen, we are getting resolutions completely out of whack. While in display settings, the Miracast screen and regular laptop screen are showing 1920x1080. the miracasted screen looks more like 1139×918.

We find if we change the screen sharing mode to extend we can then adjust the resolution to normal. But duplicate doesn't work.

Removing KB5127648 the issue entirely.

Anyone else experiencing similar issues?

Murray Thomson 10 Reputation points

2026-11-03T05:21:49.53+00:00
We have this same issue across our organisation with Miracast devices made by Microsoft, Yealink, J5Create.

The advertised display modes and detailed timing information are identical before and after the update.

For both duplicate and extend Windows is selecting the wrong active signal mode resolution for display 2.

This issue doesn't occur if the primary display resolution is set to 1920x1080 but our business laptops are all natively 1920x1200 16:10.

A workaround is to set your display res to 1920x1080 while connected to the wireless display, then this setting is remembered and is only used when connected to the wireless display device.

DxDiag also showed a change in the Microsoft Miracast display component:

Working: MiraDisp.dll version 10.0.26100.9278

Affected: MiraDisp.dll version 10.0.26100.9549

We've compared a pre-update and post-update Win11 device.

Working Windows installation:

Miracast path refresh: 30 Hz

Active signal: 1920x1080 @ 30 Hz

Affected Windows installation (this will vary depending on your displays EDID as reported via the wireless display adapter):

Miracast path refresh: 60 Hz

Active signal: 1280x1024

At this stage our testing indicates that the display path is presenting the same supported display modes to Windows before and after the update. However, after the Windows update, Windows appears to select a different Miracast output mode, changing from the working 1920x1080 @ 30 Hz signal to 1280x1024 or another listed mode.

We have confirmed that rolling back the Windows update restores correct operation.

The Intel graphics driver remained unchanged between the working and affected configurations at version 32.0.101.8826.
Alexander Fisher 20 Reputation points

2026-11-03T05:47:37.8633333+00:00

Thanks for the follow up. Your diagnosis is the exact same with the active signal. Been trying to dig around to see if there is a way to fix on the go.

Ideally hoping for any acknowledgement of the issue before the November updates are due.

3 answers

Your answer

Murray Thomson 10 Reputation points

2026-11-03T05:21:49.53+00:00

We have this same issue across our organisation with Miracast devices made by Microsoft, Yealink, J5Create.

The advertised display modes and detailed timing information are identical before and after the update.

For both duplicate and extend Windows is selecting the wrong active signal mode resolution for display 2.

This issue doesn't occur if the primary display resolution is set to 1920x1080 but our business laptops are all natively 1920x1200 16:10.

A workaround is to set your display res to 1920x1080 while connected to the wireless display, then this setting is remembered and is only used when connected to the wireless display device.

DxDiag also showed a change in the Microsoft Miracast display component:

Working: MiraDisp.dll version 10.0.26100.9278

Affected: MiraDisp.dll version 10.0.26100.9549

We've compared a pre-update and post-update Win11 device.

Working Windows installation:

Miracast path refresh: 30 Hz

Active signal: 1920x1080 @ 30 Hz

Affected Windows installation (this will vary depending on your displays EDID as reported via the wireless display adapter):

Miracast path refresh: 60 Hz

Active signal: 1280x1024

At this stage our testing indicates that the display path is presenting the same supported display modes to Windows before and after the update. However, after the Windows update, Windows appears to select a different Miracast output mode, changing from the working 1920x1080 @ 30 Hz signal to 1280x1024 or another listed mode.

We have confirmed that rolling back the Windows update restores correct operation.

The Intel graphics driver remained unchanged between the working and affected configurations at version 32.0.101.8826.
Alexander Fisher 20 Reputation points

2026-11-03T05:47:37.8633333+00:00

Thanks for the follow up. Your diagnosis is the exact same with the active signal. Been trying to dig around to see if there is a way to fix on the go.

Ideally hoping for any acknowledgement of the issue before the November updates are due.

Answer 1

The safest fleet response is to pause wider deployment of KB5127648, retain Extend as the temporary workaround, and open a Microsoft support case because the Miracast Duplicate-mode regression is not currently documented as a known issue and has no published Known Issue Rollback.

KB5127648 applies to Windows 11 24H2, 25H2, and 26H2, but its documented known issues do not include Miracast scaling or Duplicate-mode resolution problems.^1^ The Windows 11 release-health listings likewise do not currently identify this symptom.^2^

Recommended fleet action

Pause KB5127648 deployment to devices that have not received it.
- Use the existing Windows Update for Business, Intune, or update-management deferral mechanism.
- Do not indefinitely block subsequent security updates; reassess when a newer cumulative update is released.
Keep affected meeting spaces in Extend mode.
- Press Windows key + P → Extend.
- Open Settings → System → Display.
- Select the wireless display and configure the working resolution.
- This preserves KB5127648 while avoiding the faulty Duplicate-mode result.
Use removal only as a time-limited exception for business-critical devices.
- Your install/remove comparison is strong evidence of an update-triggered regression across this fleet.
- However, uninstalling a cumulative security update also removes its security fixes. Pilot the exception on a small ring and document the affected build, receiver, GPU, and Wi-Fi hardware.
- There is no published Miracast-specific KIR or Group Policy mitigation on the KB page. Do not deploy KIR packages listed for unrelated Explorer or Remote Desktop issues.
Test the next cumulative or preview update on a representative ring before restoring broad deployment:
- At least one 25H2 and one 26H2 device.
- Each major GPU/Wi-Fi combination.
- Both a Teams Rooms receiver and ScreenBeam.
- Test Duplicate at 1920×1080 and record the physical output, not only the resolution shown in Settings.

Escalation data to collect

Open a Microsoft support case and include:

Before/after OS build numbers from winver.
Confirmation that the same endpoint/receiver pair works after removing KB5127648 and fails after reinstalling it.
GPU and Wi-Fi adapter models and driver versions.
Receiver model and firmware version.
Screenshots of Settings → System → Display → Advanced display for both displays.
Photos or video showing the incorrectly proportioned output.
Results across Duplicate and Extend modes.
A minimal device/receiver matrix showing how many combinations reproduce it.

Windows hardware testing explicitly categorizes “expected resolution … found …” in a Miracast test as the driver failing to set the desired resolution, so driver and receiver details will help Microsoft isolate the affected display path.^3^

Submit the same reproduction through Feedback Hub by pressing Windows key + F, using a category related to display/casting, and attach the support case number if available. Reports from multiple affected endpoints improve correlation.

Conditional checks

Because the failure starts and stops with KB5127648, generic reconnection troubleshooting should not displace the escalation. However, if only particular hardware combinations fail:

Install the OEM-supported graphics and Wi-Fi drivers.
Update the Teams Rooms or ScreenBeam receiver firmware.
Remove and re-pair the receiver at Settings → Bluetooth & devices → Devices → Wireless displays & docks.

These are Microsoft’s standard wireless-display checks.^4^ They are most useful for separating a general Windows regression from an interaction with a specific GPU, Wi-Fi driver, or receiver firmware—not as proof that the endpoint driver caused this fleet-wide behavior.

References

Answer 2

I couldn’t find any public reports of this specific Miracast duplicate-mode problem with KB5127648, so I can’t tell you whether anyone else is seeing it. The update was released October 13 for 24H2, 25H2 and 26H2. Microsoft’s listed known issues are Smart App Control, Remote Desktop with Administrator protection, and USB Audio Class 1.0, and none of them involve Miracast or display resolution. The other reported problems are unrelated: 802.1X/PEAP Wi-Fi authentication failures and install errors such as 0x800f0845. Since you’ve confirmed that removing the KB fixes it across 25H2 and 26H2, you’ve probably found a real regression that hasn’t been written up yet.

File a Feedback Hub report under Devices and Drivers > Projecting to a PC / Wireless Display.

Try one Teams Room, one ScreenBeam and one Microsoft Wireless Display Adapter against the same laptop, and one affected laptop against several receivers. If every receiver is affected, it points to the Windows Miracast or graphics stack. If only some are, it’s probably how the sink negotiates a mode.

On the same OS build, compare machines with different GPUs (Intel, AMD, NVIDIA). Miracast duplicate mode depends on the WDDM driver, so a driver-specific pattern would be a useful detail to include in your report.

A result like 1139×918 isn’t a standard mode. It looks like scaling or a mismatched aspect ratio being applied to the encoded stream, so check whether the sender’s display scaling (100%, 125%, 150%) changes the result.

Use Windows Update for Business deferral, or WSUS or Intune declines for this KB, until you have a fix. For machines already patched, uninstalling the LCU with wusa /uninstall /kb:5127648 works, but a combined SSU+LCU package may not allow it. In that case use DISM /Online /Remove-Package with the package name. Weigh this against the update fixing an actively exploited CVE, so limit the hold to the devices that actually do wireless presenting.

Extend mode with the resolution corrected is workable for meeting rooms. You could also use “Second screen only” if you only need the room display.

Answer 3

F Grant 0

Very relieved to finally find someone else with the same issue. We are experiencing the same problem across various different devices that have the KB5127648 update.

Manually changing the device aspect ratio to 1920x1080 tends to fix the duplicate projection for us, but it then messes up the laptop's own screen resolution. Didn't have any issues with this until this update started to come through.

Alexander Fisher 20 Reputation points

2026-10-23T09:10:11.8433333+00:00

Glad it is not just us, I've tried altering a few settings but the issue persists. Was hoping to find a quick fix that wasn't rolling back the update.