Microsoft Confirms Two August Windows Update Bugs: Game Crashes and WPF Printing Failures

Microsoft has confirmed two separate problems associated with its August 11, 2026 Patch Tuesday updates—not one broad Windows failure.

The first affects some Windows 11 games when RGB hardware has installed a compatible low-level driver or software component. The second affects certain Windows Presentation Foundation (WPF) applications during printing or PDF/XPS generation when specific fonts are used. In both cases, Microsoft documented temporary mitigations, but neither notice included a dated permanent fix. 12023

1. Windows 11 games can freeze or crash because of RGB-related components

The Windows 11 issue affects version 24H2 and 25H2 systems after installation of update KB5121003. Microsoft says the problem is associated with peripherals or internal components that support RGB lighting and may install drivers or code components with names similar to inpoutx64. Launching certain games on systems containing those components can cause the game to become unresponsive, crash, fail to start, or display an access-violation error. 13

Microsoft has identified ARC Raiders, MARVEL Tōkon: Fighting Souls, and THE FINALS among the affected games. The issue is tied to the driver or software component—not to RGB lighting itself as a feature. 1816

Microsoft’s registry workaround

Microsoft’s temporary mitigation is to create or set the following DWORD value to 1 and then restart Windows:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Kernel

DisableExceptionChainValidation = 1

This is a system-wide change. It disables exception-chain validation, which is a Windows security protection. That means the workaround may restore compatibility, but it also reduces protection while enabled. Back up the registry before making the change, and revert it once Microsoft or the relevant software vendor provides a proper fix. 16

Where possible, a safer operational approach is to update, disable, or remove the RGB utility or implicated driver rather than leaving the system-wide security setting in place. Reports from game developers and technology publications specifically identify inpoutx64.sys as one component associated with the failures, although Microsoft’s wording refers more broadly to similarly named drivers or code components. 3810

Microsoft said it was investigating the problem and working toward a resolution, but it did not publish a delivery date for a permanent fix in the cited notice. 1

2. Some WPF apps fail when printing or creating PDF/XPS files

The second regression comes from the August 2026 .NET Framework cumulative updates. Certain applications built with Windows Presentation Foundation, or WPF, may fail with:

System.IO.FileFormatException

The error can occur while printing or generating PDF/XPS content that uses particular fonts. Microsoft’s update documentation names Calibri as an example; other reports identify Cambria, Constantia, and Corbel as affected fonts. 202344

This is not necessarily a general printer failure. The known issue is limited to certain WPF application workflows and can also affect applications that generate PDF or XPS output rather than sending a document directly to a physical printer. 2338

First option: substitute the affected fonts

If the application or document template allows it, replacing an affected font with an alternative can avoid the failing font-processing path while keeping the security update installed. Arial and Times New Roman are examples reported as alternatives that can restore affected output, although changing fonts may alter document layout. 39

Application-level AppContext workaround

Microsoft documents an application configuration switch that disables the affected TrueType processing protection:

<configuration>
  <runtime>
    <AppContextSwitchOverrides
      value="Switch.MS.Internal.TtfDelta.DisableCmapAndSbitOverflowProtection=true" />
  </runtime>
</configuration>

The equivalent C# setting is:

AppContext.SetSwitch(
    "Switch.MS.Internal.TtfDelta.DisableCmapAndSbitOverflowProtection",
    true);

The switch name matters: the Microsoft documentation identifies DisableCmapAndSbitOverflowProtection, not the shorter DisableTtfDelta name sometimes used in secondary descriptions. 202123

Security trade-off

This workaround turns off a protection introduced by the August update’s TrueType font-processing changes. It may make printing or PDF/XPS generation work again, but it also reduces part of the security hardening delivered by the update. Microsoft therefore presents it as a temporary, targeted mitigation—not a setting to apply broadly or leave enabled indefinitely. 2048

The .NET updates were security updates, so removing protections or uninstalling them without a specific recovery plan can increase exposure to the vulnerabilities they were intended to address. Use the narrowest workaround that resolves the problem, record the change, and remove it when Microsoft supplies a fix. 48

What affected users should do now

1. For game crashes: check whether the system has RGB-control software or a component containing a driver or file named similarly to inpoutx64.
2. For the gaming registry workaround: back up the registry, understand that DisableExceptionChainValidation weakens a system-wide security protection, and undo the change after a permanent fix is available. 16
3. For WPF printing or PDF/XPS failures: test the same document with a font such as Arial or Times New Roman before changing system-wide settings. 39
4. For application owners: use the documented AppContext switch only for affected WPF applications, and treat it as temporary because it disables part of the update’s font-processing protection. 2023
5. Track Microsoft’s release-health notices: the cited notices described both issues as under investigation or awaiting resolution and did not provide a permanent-fix timeline. 12023

The key distinction is that these are two different compatibility regressions with different triggers and different mitigations: one involves low-level RGB-related components and game startup, while the other involves WPF’s handling of selected fonts during document output.