Resolved issues in Windows 11, version 26H1

Find information on recently resolved issues for Windows 11, version 26H1. To find a specific issue, use the search function on your browser (CTRL + F for Microsoft Edge). For immediate help with Windows update issues, click here if you are using a Windows device to open the Get Help app or go to support.microsoft.com. Follow @WindowsUpdate on X for Windows release health updates. If you are an IT administrator and want to programmatically get information from this page, use the Windows Updates API in Microsoft Graph.

Resolved issues

Issue details

September 2026

Remote Desktop Services might stop responding after Sept. 2026 security update

After installing the September 2026 Windows security update (KB5124012), some organizations might experience issues with Remote Desktop Services (RDS).

In some environments, RDS might become unstable, resulting in RDP connections failing after several minutes, sign-in issues, or servers hanging at "Please wait for the Remote Desktop Configuration". Related tools, including Microsoft Management Console (MMC), RDS Licensing Diagnoser, and File Explorer might also become unresponsive. Additionally, the Windows Update page might stop responding and continuously display a loading indicator. 

Note: This issue does not affect Windows 365 or Azure Virtual Desktop.

Resolution: This issue is resolved by the out-of-band (OOB) update released on September 14, 2026 (KB5129194), and in updates released after this date.

IT administrators who deployed a temporary mitigation through Group Policy do not need to take any action before installing this OOB update.

This OOB update is cumulative and includes all improvements and security protections contained in previous Windows updates. As a best practice, we recommend installing the latest update available for your devices, as it contains important improvements and issue resolutions, including this one.

Affected platforms:

• ​Client: Windows 11, version 26H1; Windows 11, version 25H2; Windows 11, version 24H2; Windows 11, version 23H2; Windows 10, version 22H2; Windows 10, version 21H2; Windows 10 Enterprise LTSC 2019; Windows 10 Enterprise LTSC 2016
• ​Server: Windows Server 2025; Windows Server 2022; Windows Server 2019; Windows Server 2016; Windows Server 2012 R2; Windows Server 2012

Host folder shares might be unavailable in Hyper-V-based Linux VMs

Updated (9/14): The resolution section was updated. IT administrators that deployed a temporary mitigation through Group Policy must re-enable the Group Policy and install the out-of-band update to resolve the issue.

After installing the September 2026 security update KB5124012, applications that use HCS-managed virtual machines might experience issues when sharing host folder with Linux VMs using Plan9. Affected virtual machines start normally, but folders shared from the Windows host using Plan9 do not appear or cannot be accessed in the guest environment.

Applications or sandbox environments that depend on these shared folders might display an error indicating that no Plan9 drive shares were mounted. Claude Cowork and the Windows Subsystem for Linux (WSL) are two of the applications affected by this issue. Standard Hyper-V virtual machines that do not use the Plan9 feature are not affected by this issue.

Resolution: This issue is resolved by the out-of-band (OOB) update released on September 14, 2026 (KB5129194), and in updates released after this date.

IT administrators who deployed a temporary mitigation through Group Policy must re-enable the Group Policy, install this OOB update, and restart to resolve this issue.

This OOB update is cumulative and includes all improvements and security protections contained in previous Windows updates. As a best practice, we recommend installing the latest update available for your devices, as it contains important improvements and issue resolutions, including this one.

Affected platforms:

• ​Client: Windows 11, version 26H1; Windows 11, version 25H2; Windows 11, version 24H2; Windows 11, version 23H2; Windows 10, version 22H2; Windows 10, version 21H2
• ​Server: None

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Microsoft Teams and Outlook might fail to launch on ARM-based devices

After installing Windows security updates released on or after August 11, 2026, (KB5121000), Microsoft Teams and the new Outlook for Windows might fail to launch or might close unexpectedly on ARM-based devices, such as Surface Pro 11 and Surface Laptop 7. Classic Outlook, Word, Excel, and other applications are not known to be affected. This issue is most likely to occur on new or freshly imaged PCs that have not yet installed any Microsoft Store updates.

Resolution: This issue was resolved by Windows updates released September 8, 2026 (KB5124012), and updates released after that date. We recommend you install the latest update for your device as it contains important improvements and issue resolutions, including this one. 

If you install an update released September 8, 2026 (KB5124012), or later, you do not need to use a workaround for this issue. If you are using an update released before September 8 and have this issue, you have the option to apply the following workaround. 

Workaround: To work around this issue:

1. ​Open Microsoft Store.
2. ​Select Downloads > Check for updates.
3. ​Install the latest update for the Auto Super Resolution Package (version 1.0.19.0 or later).

Affected platforms:

• ​Client: Windows 11, version 26H1; Windows 11, version 25H2; Windows 11, version 24H2
• ​Server: None

August 2026

Incorrect notifications that "Microsoft Defender Antivirus is turned off"

After installing Microsoft Defender Antivirus update (version 4.18.26070.9), released on August 5, 2026, notifications might appear stating that "Microsoft Defender Antivirus is turned off," even though the antivirus is functioning correctly and all settings show it as active. These notifications can appear when Windows starts and intermittently afterward. They persist even if notification settings are turned off.

This issue can be observed in any version of Windows or Windows Server with Microsoft Defender Antivirus running with the latest Defender updates.

Resolution: This issue was resolved in Microsoft Defender Antivirus update (version 4.18.26080.4), released on September 17, 2026.

Affected platforms:

• ​Client: Windows 11, version 26H1; Windows 11, version 25H2; Windows 11, version 24H2; Windows 11, version 23H2; Windows 10, version 22H2; Windows 10, version 21H2; Windows 10 Enterprise LTSC 2019; Windows 10 Enterprise LTSC 2016
• ​Server: Windows Server 2025; Windows Server 2022; Windows Server 2019; Windows Server 2016; Windows Server 2012 R2; Windows Server 2012

July 2026

Windows Server Update Services sync operations might have issues or time out

Microsoft has identified a service degradation affecting Windows Server Update Services (WSUS). Organizations might experience increased synchronization times or sync operation timeouts on WSUS servers. This issue began in recent days, with heightened impact observed starting July 13, 2026, and service-side mitigation on Saturday July 18, 2026. After this day, synchronization times and sync operations are expected to be restored to normal.

This issue is related to a buildup of publishing metadata which is present on existing WSUS server installations as well as from the service side.

Resolution: There are two parts to the resolution of this issue.

• ​Organizations with existing WSUS server installations that are experiencing long sync times can benefit from manual steps in order to clean up unneeded metadata. This metadata is present in existing WSUS installations but can be safely removed. Detailed guidance has been provided at the following KB article: https://support.microsoft.com/help/5121986.
• ​On July 18, 2026, Microsoft deployed a service-side mitigation which returns synchronization times and sync operations back to normal for new WSUS installations and rebuilds. After this date, newly installed or rebuilt WSUS servers should not encounter this issue.

Affected platforms:

• ​Client: Windows 11, version 26H1; Windows 11, version 25H2; Windows 11, version 24H2; Windows 11, version 23H2; Windows 10, version 22H2; Windows 10, version 21H2; Windows 10, version 1809; Windows 10 Enterprise LTSC 2019; Windows 10 Enterprise LTSC 2016; Windows 10, version 1607
• ​Server: Windows Server 2025; Windows Server 2022; Windows Server, version 1809; Windows Server 2019; Windows Server 2016; Windows Server 2012 R2; Windows Server 2012

June 2026

GIF functionality in the Windows Emoji Panel might become unavailable

Starting on June 30, 2026, you might not see GIF options in the Windows Emoji Panel on some devices and instead see a message stating “GIF service is not available.” This issue occurs because the previous GIF provider (Tenor) retired its service on that date. 

Resolution: This issue was resolved by Windows updates released June 23, 2026 (KB5095091), and later. These updates include a new GIF provider (GIPHY). To restore GIF functionality in the Windows Emoji Panel, install the latest available Windows updates, which contains important improvements and issue resolutions, including this one. 

Affected platforms:

• ​Client: Windows 11, version 26H1; Windows 11, version 25H2; Windows 11, version 24H2
• ​Server: none

Deleting a file from the Recycle Bin displays an internal filename in the dialog

When permanently deleting a single item from the Recycle Bin, the confirmation dialog displays the internal Recycle Bin filename (for example, $Rxxxxx.ext) instead of the original filename. The Recycle Bin itself correctly displays the original filename, and restoring the item also restores it using the original filename.

This issue occurs after installing the Windows security update released on June 9, 2026 (KB5095051).

Resolution: This issue was resolved by Windows updates released June 23, 2026 (KB5095091), and later. We recommend you install the latest update for your device as it contains important improvements and issue resolutions, including this one. If your organization has installed an update released on June 23, 2026, or later, you do not need to use a Known Issue Rollback (KIR) or a special Group Policy to resolve this issue.

Affected platforms:

• ​Client: Windows 11, version 26H1; Windows 11, version 25H2; Windows 11, version 24H2; Windows 11, version 23H2; Windows 10, version 22H2; Windows 10 Enterprise LTSC 2021; Windows 10 Enterprise LTSC 2019; Windows 10 Enterprise LTSB 2016
• ​Server: Windows Server 2025; Windows Server 2022; Windows Server 2019; Windows Server 2016; Windows Server 2012 R2; Windows Server 2012

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