Microsoft has confirmed a Remote Desktop Services issue caused by its September 2026 Windows security update. The advisory, opened on 11 September, lists eight Windows client versions and six Windows Server versions as affected, with symptoms including RDP connections failing after several minutes. There is no public workaround yet.
Which Windows Versions Microsoft Lists as Affected
Fourteen versions appear on Microsoft’s affected-platforms list, and the client side is the part early coverage largely missed. Reports through 10 September framed the problem as a Windows Server fault; Microsoft’s advisory, published the following day, names Windows 11 and Windows 10 as well.
| Client versions listed | Server versions listed |
|---|---|
| Windows 11, version 26H1 | Windows Server 2025 |
| Windows 11, version 25H2 | Windows Server 2022 |
| Windows 11, version 24H2 | Windows Server 2019 |
| Windows 11, version 23H2 | Windows Server 2016 |
| Windows 10, version 22H2 | Windows Server 2012 R2 |
| Windows 10, version 21H2 | Windows Server 2012 |
| Windows 10 Enterprise LTSC 2019 | — |
| Windows 10 Enterprise LTSC 2016 | — |
Microsoft frames the fault as affecting “some organizations” and “some Windows devices with Remote Desktop enabled,” so being on the list does not mean a machine will break. Remote Desktop Services is the Windows component that hosts remote sessions, the technology behind both single-PC remote access and the multi-user terminal servers many businesses run.
What Goes Wrong
Microsoft’s advisory describes instability rather than an outright failure to start. Its published description lists these symptoms: “RDP connections failing after several minutes, sign-in issues, or servers hanging at ‘Please wait for the Remote Desktop Configuration’.”
Three other things can seize up alongside it, according to the same advisory: Microsoft Management Console, the RDS Licensing Diagnoser and File Explorer may stop responding, and the Windows Update page itself may hang on a loading indicator.
Administrators quoted by BleepingComputer on 10 September described a sharper version of the same pattern. One said every terminal server in their environment failed within a day, with sessions dropping and no new connections possible until a hard reset. Another reported that services crashed after the first log-out and no further users could sign in, and that restarting the server did not help.
Which Updates Started It
The trigger is the 8 September 2026 security update, which carries a different KB number for each product.
| Product | Update |
|---|---|
| Windows 11 (OS Build 28000.2954) | KB5124012 |
| Windows Server 2022 (OS Build 20348.5622) | KB5122882 |
| Windows Server 2019 | KB5122876 |
| Windows Server 2025 | KB5122871 |
The Windows 11 and Server 2022 builds are named in Microsoft’s own advisory; the Server 2019 and Server 2025 numbers come from BleepingComputer’s reporting.
Why Uninstalling the Update Is a Poor Trade
Removing the September update restores Remote Desktop, but it also removes a month of fixes that matter more than most. Tenable, the vulnerability management company, counted 964 CVEs in this release, 104 of them critical.
- CVE-2026-69525: a use-after-free remote code execution flaw in Remote Desktop Services itself, scored 9.8 out of 10 on the CVSS scale and rated “Exploitation More Likely” by Microsoft.
- CVE-2026-81963: an elevation-of-privilege flaw in the Windows Update Stack, CVSS 7.8, already exploited in the wild.
- CVE-2026-85880: an elevation-of-privilege flaw in Windows Advanced Local Procedure Call, CVSS 7.8, also already exploited.
In other words, the update that destabilises Remote Desktop Services is the same one that closes a critical hole in Remote Desktop Services. Anyone considering a rollback on an internet-facing RDS host is trading a reliability problem for an exposure that attackers are more likely to reach. Comparable months have been far lighter: a 2024 Patch Tuesday closing 90 vulnerabilities counted as a large release at the time.
What Microsoft Says to Do
As of 12 September 2026 the issue is marked Confirmed and unresolved, opened and last updated at 11:19 Pacific Time on 11 September. Microsoft’s instruction is narrow: “IT administrators who need an immediate workaround should contact Microsoft Support for Business for assistance.” It adds that it is “working to release a resolution in a future Windows update.”
That leaves no self-service fix published. Microsoft has not given a target date for the resolution, has not said how many organisations are affected, and has not published a registry change or configuration step of the kind it sometimes offers while a patch is prepared. Organisations running Windows Server 2025 and the five older server releases are all on the list.
A Second Confirmed Bug in the Same Update
KB5124012 carries a separate confirmed issue on Windows 11, opened earlier on 11 September. Host folders shared from Windows into Linux virtual machines using Plan9 may not appear or cannot be opened inside the guest, and Microsoft names the Windows Subsystem for Linux among the affected applications. Standard Hyper-V virtual machines that do not use Plan9 are unaffected, and Microsoft says a resolution is being worked on.
Frequently Asked Questions
Common questions about the Remote Desktop Services issue in the September 2026 Windows update.
Which Windows Versions Are Affected by the Remote Desktop Services Issue?
Microsoft lists eight client versions (Windows 11 26H1, 25H2, 24H2 and 23H2, Windows 10 22H2 and 21H2, and Windows 10 Enterprise LTSC 2019 and LTSC 2016) and six server versions (Windows Server 2025, 2022, 2019, 2016, 2012 R2 and 2012).
Which Update Caused the Remote Desktop Services Issue?
The 8 September 2026 security update. Microsoft’s advisory names KB5124012 for Windows 11 and KB5122882 for Windows Server 2022; BleepingComputer reported KB5122876 for Windows Server 2019 and KB5122871 for Windows Server 2025.
Is There a Fix for the Remote Desktop Services Issue Yet?
No. As of 12 September 2026 the issue is marked Confirmed and unresolved. Microsoft says a resolution will come in a future Windows update and has not given a date.
Should I Uninstall the September 2026 Windows Update?
Uninstalling restores Remote Desktop but removes the month’s security fixes, including CVE-2026-69525, a remote code execution flaw in Remote Desktop Services scored 9.8 on CVSS, and two elevation-of-privilege flaws already being exploited. Microsoft’s own guidance is to contact Support for Business for a workaround instead.
What Are the Symptoms of the Remote Desktop Services Issue?
RDP connections failing after several minutes, sign-in problems, and servers hanging at \u201cPlease wait for the Remote Desktop Configuration\u201d. Microsoft Management Console, the RDS Licensing Diagnoser, File Explorer and the Windows Update page may also stop responding.
