| Problem | Cause | Solution |
|---------|-------|----------|
| F1 extracted as .cid not .ttf | CID is a raw glyph set | Use tx tool or FontTools to rebuild TTF |
| Subset lacks certain glyphs | Only embedded used chars | Download full base font |
| Error: “Cannot find /F4” | PDF references a font not embedded | Extract font name via pdffonts → download missing |
| Free download site malware | Scam sites offering “F1 font” | No real font named F1; use Noto/Source instead |
Instead of hunting for suspicious "F1 F2 F3" files (which do not exist as standard font names), download these free, open-source font families that will automatically satisfy CID requests when properly aliased. cid font f1 f2 f3 f4 f5 f6 f7 fonts free download work
# Identify real font names
pdffonts document.pdf