Major Glitch Hits WPF Apps, Printing and PDF Export Broken by Latest Microsoft Updates
In a significant issue affecting thousands of users worldwide, Microsoft has confirmed that its recent .NET Framework updates have broken printing and PDF export capabilities in certain applications. The problem specifically affects apps built using the Windows Presentation Foundation (WPF) UI framework, an open-source graphical subsystem for building Windows desktop client applications.
The glitch, which has been reported to affect both Windows client releases (including the latest versions of Windows 10 and Windows 11) and Windows Server (from Windows Server 2012 up to Windows Server 2025), causes WPF apps to fail when printing or generating PDF/XPS content that uses certain fonts, including Calibri. Microsoft has acknowledged the issue in a Windows release health alert and is currently investigating the cause.
To help affected users work around this problem, Microsoft has provided a temporary fix, which involves enabling an AppContext switch in the application config file. However, doing so will disable protections introduced with the August 2026 .NET Framework update, leaving systems vulnerable to attacks that could exploit vulnerabilities addressed by this month’s security updates.
It’s worth noting that this is not the first time Microsoft has encountered issues affecting WPF apps. In February 2021, the company addressed a similar problem that caused WPF apps and Visual Studio to crash after installing Windows 10 cumulative updates. This latest issue may be particularly concerning for organizations that rely heavily on WPF-based applications.
The temporary fix provided by Microsoft is not without risks. While it can help users print and export PDFs, it also compromises the security of their systems. As such, Microsoft strongly advises against using this workaround unless absolutely necessary to address the issue.
For users who are experiencing problems with printing or PDF export in WPF apps, there are a few options available. If possible, try uninstalling the August 2026 .NET Framework update and see if that resolves the issue. Alternatively, you can use the temporary fix provided by Microsoft, but be aware of the risks involved.
In any case, it’s essential to keep an eye on updates from Microsoft and stay informed about potential issues affecting your applications. By doing so, you’ll be better equipped to handle problems like this one and ensure that your systems remain secure and functional.
Source: Bleeping Computer — 2026-08-24