mozilla/pdf.js · error · FormatError

TrueType Collection does not contain "${fontName}" font.

Error message

TrueType Collection does not contain "${fontName}" font.

What it means

Thrown by readTrueTypeCollectionData() after scanning all member fonts in a TTC and finding none whose 'name' table entries match the requested fontName — and no partial fallback match was found either. The PDF references a specific font name that the TTC does not contain.

Source

Thrown at src/core/fonts.js:1598

                  header: potentialHeader,
                  tables: potentialTables,
                };
              }
            }
          }
        }
      }
      if (fallbackData) {
        warn(
          `TrueType Collection does not contain "${fontName}" font, ` +
            `falling back to "${fallbackData.name}" font instead.`
        );
        return {
          header: fallbackData.header,
          tables: fallbackData.tables,
        };
      }
      throw new FormatError(
        `TrueType Collection does not contain "${fontName}" font.`
      );
    }

    /**
     * Read the appropriate subtable from the cmap according to 9.6.6.4 from
     * PDF spec
     */
    function readCmapTable(cmap, file, isSymbolicFont, hasEncoding) {
      if (!cmap) {
        warn("No cmap table available.");
        return {
          platformId: -1,
          encodingId: -1,
          mappings: [],
          hasShortCmap: false,
        };
      }

View on GitHub (pinned to 5903d58d58)

Solutions

Inspect the TTC member font names with fonttools: [TTFont('file.ttc', fontNumber=i)['name'].getDebugName(1) for i in range(count)] and compare with the PDF's BaseFont name.
Ensure the PDF's font resource name matches a name table entry (nameID 1 or 4/6) in the TTC.
Rebuild the PDF ensuring the correct font from the TTC is referenced.
If the font name includes a subset prefix (XXXX+), verify it matches the embedded subset.

Example fix

# find which font names exist in the TTC
from fontTools import ttLib

ttc = ttLib.TTCollection('fonts.ttc')
for i, font in enumerate(ttc.fonts):
    name = font['name'].getDebugName(1)  # Family name
    post = font['name'].getDebugName(6)  # PostScript name
    print(f'{i}: {name} / {post}')
# then fix the PDF to reference the matching PostScript name

Defensive patterns

Strategy: validation

Validate before calling

// Server-side: list all names in the TTC and compare with the PDF's BaseFont
// from fontTools import ttLib
// ttc = ttLib.TTCollection('fonts.ttc')
// available = set()
// for font in ttc.fonts:
//     for record in font['name'].names:
//         available.add(record.toUnicode())
// if pdfBaseFont not in available:
//     print(f'{pdfBaseFont} not found in TTC')

Try / catch

try {
  await page.render(renderParams).promise;
} catch (err) {
  if (err.message?.includes('TrueType Collection does not contain')) {
    console.error('Font name mismatch between PDF and embedded TTC; check BaseFont name.');
  } else { throw err; }
}

Prevention

Ensure the PDF's BaseFont name exactly matches a name table entry (nameID 6 PostScript name) in the TTC.
Verify subset prefixes (XXXX+) in the PDF match the embedded subset's names.
When updating a TTC, regenerate the PDF so font references stay in sync.

When it happens

Trigger: The loop over numFonts completes without returning (no exact nameEntry === fontName match), fallbackData remains null (no fontNameParts partial match), and execution reaches the final throw. The fontName comes from the PDF's font resource name (e.g., 'ABCDEF+Arial').

Common situations: The PDF references a font subset prefix (e.g., 'ABCDEF+TimesNewRoman') that doesn't match any name in the TTC. The TTC was replaced or updated but the PDF still references old font names. A mismatch between the PDF's BaseFont name and the actual embedded TTC member names. The fontName uses a different naming convention than the TTC member.

Related errors

AI-assisted analysis of mozilla/pdf.js@5903d58d58 (2026-08-13). Data as JSON: /api/errors/10b809f03a7f9fc2. Report an issue: GitHub.