keras-team/keras · error · ValueError

Invalid value for argument `synchronization`. Expected one o

Error message

Invalid value for argument `synchronization`. Expected one of `None`, `'none'`, `'on_read'`, `'on_write'`, `'auto'`. Received: synchronization={synchronization}

What it means

Error "Invalid value for argument `synchronization`. Expected one of `None`, `'none'`, `'on_read'`, `'on_write'`, `'auto'`. Received: synchronization={synchronization}" thrown in keras-team/keras.

Source

Thrown at keras/src/backend/common/variables.py:136

            "sum",
            "only_first_replica",
        ):
            raise ValueError(
                "Invalid value for argument `aggregation`. Expected "
                "one of `None`, `'none'`, `'mean'`, `'sum'`, "
                "`'only_first_replica'`. "
                f"Received: aggregation={aggregation}"
            )
        if aggregation is None:
            aggregation = "none"
        if synchronization not in (
            None,
            "none",
            "on_read",
            "on_write",
            "auto",
        ):
            raise ValueError(
                "Invalid value for argument `synchronization`. Expected "
                "one of `None`, `'none'`, `'on_read'`, `'on_write'`, "
                "`'auto'`. "
                f"Received: synchronization={synchronization}"
            )
        if synchronization is None:
            synchronization = "none"
        self._name = name
        parent_path = current_path()
        if parent_path:
            self._path = f"{parent_path}/{name}"
        else:
            self._path = name
        self._shape = None
        self._initializer = None
        self._regularizer = None
        self._constraint = None
        self._trainable = bool(trainable)

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/backend/common/variables.py:136 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of keras-team/keras@7a34a03db6 (2026-08-25). Data as JSON: /api/errors/6491ce74d8bcac63. Report an issue: GitHub.