Winners & losers: Microsoft has released an out-of-band update to repair the damage from September's Patch Tuesday. That release fixed nearly 1,000 vulnerabilities across Microsoft's products and broke a number of things along the way. The emergency patch fixes Remote Desktop failures, a virtualization bug, and part of an audio problem. Several of the most disruptive complaints remain unresolved, including AMD Radeon crashes and Explorer failing to load.
The emergency fix arrives as KB5129195 for Windows 11 24H2 and 25H2. It is a mandatory cumulative update that installs automatically, so users who skipped the bigs September 8 release (KB5124008) will get its changes as well.
Microsoft also shipped matching packages for Windows 11 26H1 and 23H2, Windows 10 21H2 and 22H2, and several Windows Server and LTSC releases. Eligible 24H2 and 25H2 machines can apply a "hotpatch" without a restart, but those are kind of a miracle in Windows update terms.
The fixes cover three of the regressions Microsoft had already acknowledged. The first is Remote Desktop Services. After the September update, RDS could become unstable, causing RDP connection and sign-in failures. The Microsoft Management Console, RDS Licensing Diagnoser, File Explorer, and even the Windows Update page could also stop responding.
The second fix targets apps that run Linux virtual machines through the Host Compute Service. Claude Cowork was among the casualties: its workspace lost access to local files, and Anthropic added an in-app error message that blamed the Windows update.
The third fix restores 8-channel and 3D modes on some USB audio devices that still worked in plain stereo, but this audio fix only goes part of the way. Microsoft still lists a known issue in which some devices fail to start in Device Manager, produce no sound, or show volume controls stuck at zero.
The update also closes a privilege escalation flaw that September's patch hadn't fully fixed. On 26H1, it additionally patches a Secure Kernel Mode elevation bug.
The problem most likely to worry PC gamers is also absent from the changelog. Radeon owners have reported driver timeouts, black screens, displays dropping out, and full system freezes after installing the September update. The reports span several generations, from the RX 6600 through the RX 7000 series to the RX 9070 XT, but not every Radeon system is affected. Some users report that uninstalling the September update resolves the crashes.
Two other problems remain officially unconfirmed. The first is Explorer.exe failing to start or crashing, which leaves users with a black screen and no taskbar. So far these reports mostly come from enterprise setups using tools such as Citrix and FSLogix. A Microsoft employee responding on Reddit described the September release as "extensive" and asked affected admins to submit memory dumps. The second is File History no longer detecting external backup drives.
The scale of the September release helps explain the problems. It was a Patch Tuesday record where Microsoft addressed between 964 and 974 CVEs, depending on who's counting, with 723 of them in Windows alone. For comparison, the same month in 2025 brought fewer than 100.
The big jump follows Microsoft's shift to in-house AI tools for vulnerability discovery. Days before the problems surfaced, the company had urged users not to delay updates, arguing that attackers using AI can quickly exploit known gaps. On the other hand, out-of-band patches that were once rare have now become routine: Microsoft shipped several in January, two in March, another in July, and now this one – despite the company's pledge earlier this year to prioritize stability.