Microsoft’s Update Breaks Printing for Certain Fonts on Windows 11

Microsoft's August 2026 .NET Framework update has caused problems for Windows 11 users who print WPF documents using certain fonts. Specifically, Calibri, Cambria, Constantia, and Corbel fonts are affected by a 'System.IO.FileFormatException' error when printing or generating PDF/XPS content.

The issue is not the first problem to arise from Microsoft's recent update. Windows 11 has also been prone to crashing and freezing when running games alongside RGB peripherals after installing the update.

Microsoft has provided a workaround for users who want to maintain their system's security, but it involves disabling protections introduced in the August 2026 update. This can be done by adding an 'AppContext' override to the application's configuration file or by using a different font.