Ensure you have the following fonts installed on your system: Tahoma Segoe UI

To solve this, Microsoft created "shell dialog" virtual fonts. When a program requests "Ms Shell Dlg," Windows essentially translates that request and substitutes it with the operating system's default UI font.

Windows uses this mapping to ensure that user interfaces (like dialog boxes) look consistent and support local characters across different languages and Windows versions. Common Mappings

Think of it as a placeholder or a nickname. When early versions of Windows were developed, developers faced a problem: they wanted the user interface to look consistent, but they couldn't guarantee which fonts were installed on every user's machine. Furthermore, different versions of Windows used different default system fonts.

Because downloading a mythical "ms_shell_dlg.ttf" file from a random font website will not solve any problem. Instead, you need to ensure the target fonts (Microsoft Sans Serif, MS Sans Serif, or Tahoma) are installed and the registry mappings are intact.

Since MS Shell Dlg is just a pointer, you likely need the actual fonts it points to. These are standard Microsoft system fonts: Can Not Find MS Shell Dlg 2 - LightBurn Software Forum

If you want your application or design to feel modern and fit seamlessly into the Windows 10/11 environment, you want Segoe UI.