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Unknown project type

project
_quarto.yml sets a project.type that is neither built-in nor contributed by an installed extension; the render stops.

Q-5-17 — Unknown project type

_quarto.yml sets a project.type that is neither built-in nor contributed by an installed extension; the render stops.

What this means

project.type decides how every document in the project is processed. Quarto resolves it against two sources: the built-in types (default, website, book, manuscript) and the types contributed by extensions in _extensions/ via contributes: project:.

When neither matches — or when the value is not a string at all — the render stops before any document is processed.

Stopping is deliberate. Earlier Quarto 2 versions continued with default-project behavior, and that turned out to be the worse failure: a broken site build looks like a successful one, and every document gets its own copy of the shared JS and CSS written next to the source file, littering the tree. An error at the start is easier to act on than a scattered mess at the end.

Why this happens

  • A typo in the type name.
  • An extension that is not installed in this project. Extensions are per-project; one installed elsewhere is not visible here.
  • An extension whose manifest failed to load. This is the cause worth checking first — look for a Q-16-1 warning alongside this error. A broken _extension.yml means the extension contributes nothing, and its project type becomes unknown.
  • A non-string value, such as a list or a mapping, usually from YAML indentation that nested more than intended.

How to fix

The error’s hints list the project-contributing extensions Quarto did find, which is the fastest way to spot a near-miss in the name.

For a built-in type, use one of the four:

project:
  type: website

For an extension type, install it and use the full organization/name form:

q2 add <owner>/<repo>
project:
  type: my-org/docs

If a Q-16-1 was reported next to this error, fix that manifest first — this error usually goes with it.