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Key Takeaways
- September 2026 security updates can destabilize Remote Desktop Services (RDS) on Windows Server, causing hangs and connection failures.
- Microsoft has confirmed the issue across Windows Server 2012 through Windows Server 2025, plus select Windows client builds.
- The only current workaround — uninstalling the update — trades RDS stability for the loss of this month’s security fixes.
What’s Going On
If your Remote Desktop sessions have started hanging, refusing to disconnect, or simply failing to connect after this month’s patch cycle, you’re not alone. Microsoft has confirmed that the September 2026 Windows Server security updates are causing Remote Desktop Services (RDS) instability across a wide range of supported platforms.
The frustrating part for admins: affected servers often look completely healthy right after the update installs. The problems tend to surface hours later, once sessions start piling up or connection attempts increase — which makes this a classic “it worked fine yesterday” incident.
Who’s Affected
According to Microsoft, the issue spans a broad version range, so don’t assume you’re safe just because you’re not on the newest build:
| Platform | Status |
|---|---|
| Windows Server 2012 – 2012 R2 | Confirmed affected |
| Windows Server 2016 | Confirmed affected |
| Windows Server 2019 | Confirmed affected |
| Windows Server 2022 | Confirmed affected |
| Windows Server 2025 | Confirmed affected |
| Select Windows client builds | Confirmed affected |
Symptoms to Watch For
- RDP connections that fail after several minutes rather than immediately
- Sign-in issues on otherwise reachable servers
- Servers hanging at “Please wait for the Remote Desktop Configuration”
- MMC, RDS Licensing Diagnoser, and File Explorer becoming unresponsive
- The Windows Update page spinning indefinitely without completing
RDS might become unstable, resulting in RDP connections failing after several minutes, sign-in issues, or servers hanging.
— Microsoft, Windows release health notes
What IT Admins Should Do Now
Microsoft’s official workaround is straightforward but unpleasant: uninstall the September update. Doing so restores RDS functionality, but it also strips out the security fixes that shipped in the same Patch Tuesday release — not a trade you want to make on internet-facing infrastructure without a plan.
Practical Steps
- Inventory first. Identify every server running RDS, RD Gateway, or RD Session Host roles before you touch anything — don’t patch or roll back blind.
- Check Known Issue Rollback (KIR) policies. Microsoft has published KIR group policies for enterprise environments — deploy these instead of a blanket uninstall where possible, since KIR reverts the specific behavior without pulling the whole security patch.
- Restart before you panic. For affected VMs, a stop/start cycle (not just a reboot) has restored connectivity in several reported cases.
- Stagger future patching. Push this update to a pilot ring of non-critical RDS hosts first and monitor for a few hours — the delayed onset means a quick smoke test right after patching won’t catch it.
- Document the tradeoff. If you do uninstall the update on a given host, log it as a known, time-boxed security gap so it doesn’t get forgotten in six months.
- Watch for the permanent fix. Microsoft says it’s investigating the root cause; treat KIR and rollback as bridges, not destinations.
Lab Tip
- If you run a home lab or test environment with a spare Windows Server 2019/2022 VM, this is a good excuse to snapshot it, apply the September update, and reproduce the RDS hang yourself before it hits production. Seeing the failure pattern firsthand makes it much easier to recognize on a help desk ticket.
Bottom Line
This is a good reminder that “patched” and “stable” aren’t the same thing, especially for RDS-heavy environments like RDSH farms, jump boxes, and virtual desktop hosts. Until Microsoft ships a permanent fix, lean on Known Issue Rollback policies where you can, and keep a documented, reversible plan for any server where you have to choose between this month’s security patch and keeping Remote Desktop usable.
