hiyouga/LlamaFactory · error · ImportError

mcore_adapter is not installed. Please install it with `pip

Error message

mcore_adapter is not installed. Please install it with `pip install mcore-adapter`.

What it means

Error "mcore_adapter is not installed. Please install it with `pip install mcore-adapter`." thrown in hiyouga/LlamaFactory.

Source

Thrown at src/llamafactory/train/mca/workflow.py:43

from ...data import (
    SFTDataCollatorWith4DAttentionMask,
    get_dataset,
    get_template_and_fix_tokenizer,
)
from ...data.collator import (
    PairwiseDataCollatorWithPadding,
)
from ...extras.constants import IGNORE_INDEX, MCA_SUPPORTED_MODELS
from ...extras.logging import get_logger
from ...extras.misc import calculate_tps
from ...extras.packages import is_mcore_adapter_available
from ...extras.ploting import plot_loss
from ...model import load_tokenizer
from ..callbacks import SaveProcessorCallback


if not is_mcore_adapter_available():
    raise ImportError("mcore_adapter is not installed. Please install it with `pip install mcore-adapter`.")

from mcore_adapter.models import AutoConfig, AutoModel
from mcore_adapter.trainer import DPOTrainer as McaDPOTrainer
from mcore_adapter.trainer.dpo_config import DPOConfig

from .trainer import CustomMcaTrainer


if TYPE_CHECKING:
    from mcore_adapter.training_args import Seq2SeqTrainingArguments as McaSeq2SeqTrainingArguments
    from transformers import TrainerCallback

    from ...hparams import DataArguments, FinetuningArguments, ModelArguments


logger = get_logger(__name__)

View on GitHub (pinned to f28afaf635)

Solutions

1. Install the mcore_adapter package: pip install mcore-adapter.

Example fix

pip install mcore-adapter

When it happens

Trigger: Thrown at src/llamafactory/train/mca/workflow.py:43 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of hiyouga/LlamaFactory@f28afaf635 (2026-08-14). Data as JSON: /api/errors/2a26e4d51f882909. Report an issue: GitHub.