TTF / OTF / WOFF Font Inspector will not open? Format and display troubleshooting
Troubleshoot TTF / OTF / WOFF Font Inspector by checking signatures, versions, units, coordinates, and browser resources while preserving the source.
Do not rename or overwrite the source first
Make a sample copy and retain the original delivery, size, producer version, and exact error. Search a target character and code point, confirm cmap maps it to a glyph other than .notdef, then inspect family/subfamily, PostScript name, fsType embedding bits, and the wght axis range. Metadata still does not replace the license.
Recommended troubleshooting order
- Test the page example or a smaller known-good file to confirm browser functionality.
- Check that the file signature matches its extension and it is not a downloaded HTML error page.
- Compare the supported formats and size limit with the specialist checks below.
- Close other heavy tabs and retry in current Chrome or Edge.
- If it still fails, re-export from the producing application and verify in authoritative specialist software.
Checks for this format
- The target character has a Unicode cmap mapping that is not .notdef
- Family, subfamily, and PostScript names do not collide with another font
- Version, copyright, license URL, and embedding bits are recorded
- Variable-axis min/default/max are plausible and the test value is in range
Common errors and fixes
Preview text still uses the system font
The target glyph may be absent and fall back; confirm the glyph mapping rather than visual appearance alone.
WOFF2 cannot be parsed
Browser decoding or font tables may be incompatible; try the original TTF/OTF and confirm the download was not HTML/CSS.
When a browser tool is insufficient
- Font metadata is not complete legal permission
- Complex GSUB/GPOS, color glyphs, and hinting may be partially represented
- No circumvention of encryption, DRM, or embedding restrictions
A visible preview only proves this parser read some structures. It does not prove engineering, manufacturing, scientific, business, or clinical compliance. Keep validation records from the source and receiving systems.
Privacy and safety
The tool reads files locally and does not upload them to FreeTool for parsing. Troubleshooting screenshots, CSV exports, and downloads can still contain sensitive data; de-identify before sharing and clear copies from shared devices.