Windows Update breaks WPF TrueType font subsetting (Calibri.ttf format specification error) KB5120708
Microsoft have released an update that has the potential to break Formate eVo, if certain fonts are used and the document is printed directly by Formate
An 11th August update, KB5120708 for Windows 11 25H2 has broken WPF printing if certain fonts are used;
The Fonts which work (Pass) and fail are;
- Fails: Calibri, Cambria, Constantia, Corbel (all weights/styles)
- Passes: Consolas, Candara, and even Calibri Light — plus all the older TrueType fonts (Arial, Times New Roman, Verdana, Tahoma, Georgia, Courier New)
In the formate eVo Event log you will see an error, reporting a path to the Font file like this
“‘file:///C:/WINDOWS/FONTS/CALIBRI.TTF’ file does not conform to the expected file format specification.”
This is NOT an Formate eVo fault, this is an underlying bug introduced into the .Net Widows System by the recent MS update. In addition to KB5120708 (Windows 11 25H2) reports indicate that these updates introduce the same bug into other versions of Windows
- KB5120705 (Server 2022)
- KB5120701 (Windows 10 21H2/22H2)
- KB5120710 (Windows 11 24H2)
- KB5120713 (Windows 11 23H2)
Potential Solutions offered by MS today are
- Wait for fix to be released
- Rollback Update causing the problem
- Change Fonts used by originating system, Formate eVo in this case.
At this stage, no timeline on a MS fix is available, so the other options will need to be considered should you experience the problem.
More Information is available at