August’s Home windows 11 replace breaks printers and PDFs. Microsoft explains why

Microsoft confirms that, following the set up of this replace, some purposes might encounter errors when printing from paperwork containing sure widespread fonts, or when creating PDF or XPS recordsdata:

Identified Points: After putting in the August 2026 .NET Framework cumulative replace, some WPF purposes might fail with a System.IO.FileFormatException when printing or producing PDF/XPS content material that makes use of sure fonts, together with Calibri.

The matter remains to be being investigated, however within the meantime you should use a brief workaround when you’re experiencing these points:

Workaround: Purposes might mitigate the difficulty by enabling the Change.MS.Inner.TtfDelta.DisableCmapAndSbitOverflowProtection AppContext swap within the app config file, as proven under.

This swap disables safety protections launched within the August 2026 replace and will enhance publicity to the vulnerabilities addressed by that replace. Microsoft recommends utilizing this workaround solely as a brief measure and solely when required to deal with this situation.

August 2026’s Patch Tuesday is popping into an ever-growing catastrophe for Home windows 11 customers. Yesterday, Microsoft admitted that the KB5121003 replace was additionally inflicting issues, primarily affecting players.