denoland/deno · error · AnyError

malformed .msi: no _StringPool stream

Error message

malformed .msi: no _StringPool stream

What it means

deno desktop's Windows installer repacks an existing .msi by directly editing its OLE compound-file streams (after de-mangling stream names). _StringPool is the MSI string-table header stream every valid MSI must contain; its absence means the input is not a well-formed MSI database — wrong file type, truncated template, or stream names mangled beyond what msi_demangle_stream_name can undo.

Solutions

1. Verify the input is a real MSI database: `file template.msi` (should say 'Composite Document File') and open it with lessmsi or msidb to confirm streams exist.
2. Re-obtain the pristine .msi template (re-download/rebuild) — a valid MSI always has _StringPool and _StringData.
3. If the template is custom-built, generate it with a standard tool (WiX) so the system-table streams exist.
4. Check that no earlier repack step already rewrote stream names into a form the demangler cannot reverse.

Example fix

# before: wrong file handed to the repack
file installer/template.msi
# PE32 executable (GUI)  -> it is a bootstrapper .exe, not an .msi

# after: supply the real database
file installer/template.msi
# Composite Document File V2 Document  -> OK, re-run the build

# Validate the template is a real MSI with the expected system streams before repacking
file template.msi | grep -q 'Composite Document File' || { echo 'not an OLE/MSI file'; exit 1; }
7z l template.msi | grep -q '_StringPool' || { echo 'no _StringPool stream'; exit 1; }

Catch the 'malformed .msi' family, re-check the file signature out-of-band, and fail the installer build with 'template is not a valid MSI' — retrying the same input is pointless since the file on disk will not change.

When it happens

Trigger: find_raw("_StringPool") finds no stream whose de-mangled name ends with _StringPool: passing a non-MSI file as the installer template, a corrupted/truncated .msi, or an .msi produced by a tool that names/encodes streams in an unexpected way.

Common situations: The bundled installer template was replaced or corrupted in a fork; a download of the template was truncated; the file is actually an .exe bootstrapper rather than the .msi database; a repack pipeline fed the output of a previous failed run back in as input.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• malformed .msi: no _Columns stream
• malformed .msi: no _StringData stream
• cabinet file missing
• Cannot build a .msi from an empty app directory
• deno.json `version` " " cannot be used as an MSI…

AI-assisted analysis of denoland/deno@f7822238ca (2026-08-20). Data as JSON: /api/errors/ec16d87ff6f3768b. Report an issue: GitHub.

Appendix: source

Thrown at cli/tools/desktop.rs:5291

  let write_stream = |comp: &mut cfb::CompoundFile<std::fs::File>,
                      raw: &str,
                      bytes: &[u8]|
   -> Result<(), AnyError> {
    let mut s = comp.open_stream(format!("/{raw}"))?;
    s.write_all(bytes)?;
    Ok(())
  };
  let find_raw = |suffix: &str| -> Option<String> {
    names
      .iter()
      .find(|n| msi_demangle_stream_name(n).ends_with(suffix))
      .cloned()
  };

  // The string-pool header's top bit selects 3-byte string references; tiny
  // databases use 2-byte refs, but honor the flag to stay correct at any size.
  let pool_raw = find_raw("_StringPool").ok_or_else(|| {
    deno_core::anyhow::anyhow!("malformed .msi: no _StringPool stream")
  })?;
  let pool = read_stream(&mut comp, &pool_raw)?;
  let str_w: usize = if pool.len() >= 4 && (pool[3] & 0x80) != 0 {
    3
  } else {
    2
  };

  // Map every string-pool id to its text so data-table streams (named by table
  // text) can be matched to their column schema (keyed by table string id).
  let data_raw = find_raw("_StringData").ok_or_else(|| {
    deno_core::anyhow::anyhow!("malformed .msi: no _StringData stream")
  })?;
  let str_data = read_stream(&mut comp, &data_raw)?;
  let mut strings = vec![String::new()]; // 1-based; index 0 is unused.
  {
    let mut off = 0usize;
    let mut i = 4;

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