mozilla/pdf.js · warning · FormatError

The Linearization dictionary doesn't point to a valid Page d

Error message

The Linearization dictionary doesn't point to a valid Page dictionary.

What it means

FormatError thrown by _getLinearizationPage when the object referenced by the linearization dictionary's H array (or page reference) is not a valid Page dictionary (not a Dict, or missing Type=Page / Contents without Kids). It is wrapped in a try/catch: the message is logged as a warning and pdf.js falls back to catalog.getPageDict, so end users usually never see the raw error.

Source

Thrown at src/core/document.js:1683

        if (type instanceof Ref) {
          type = await xref.fetchAsync(type);
        }
        if (
          isName(type, "Page") ||
          (!obj.has("Type") && !obj.has("Kids") && obj.has("Contents"))
        ) {
          if (!catalog.pageKidsCountCache.has(ref)) {
            catalog.pageKidsCountCache.put(ref, 1); // Cache the Page reference.
          }
          // Help improve performance of the `Catalog.getPageIndex` method.
          if (!catalog.pageIndexCache.has(ref)) {
            catalog.pageIndexCache.put(ref, 0);
          }

          return [obj, ref];
        }
      }
      throw new FormatError(
        "The Linearization dictionary doesn't point to a valid Page dictionary."
      );
    } catch (reason) {
      warn(`_getLinearizationPage: "${reason.message}".`);
      return catalog.getPageDict(pageIndex);
    }
  }

  getPage(pageIndex) {
    const cachedPromise = this.#pagePromises.get(pageIndex);
    if (cachedPromise) {
      return cachedPromise;
    }
    const { catalog, linearization, xfaFactory } = this;

    let promise;
    if (xfaFactory) {
      promise = Promise.resolve([Dict.empty, null]);

View on GitHub (pinned to 5903d58d58)

Solutions

1. Re-linearize with qpdf --linearize or Acrobat's Save As Optimized.
2. If you control delivery, ensure the byte range serving (Range requests) returns the full linearization section.
3. Suppress the warning in logs if recovery is working—the viewer will still render via the catalog fallback.

When it happens

Trigger: A 'linearized' PDF whose hint table points to a non-Page object; a corrupt linearization header; a producer that wrote a linearization dict without proper Page references.

Common situations: Bad linearization from buggy producers or aggressive PDF optimizers; partially downloaded linearized PDFs where the referenced object is missing.

Related errors

• Page count is not an integer.
• unknown encryption method
• unsupported encryption algorithm
• invalid key length
• Invalid crypt filter name.

AI-assisted analysis of mozilla/pdf.js@5903d58d58 (2026-08-13). Data as JSON: /api/errors/5fd139f9bbb70540. Report an issue: GitHub.