# 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte (dataset)

**URL:** <https://discuss.huggingface.co/t/utf-8-codec-cant-decode-byte-0xff-in-position-0-invalid-start-byte-dataset/87371>\
**Category:** Beginners\
**Created:** [May 19, 2024, 10:02am UTC](https://discuss.huggingface.co/t/utf-8-codec-cant-decode-byte-0xff-in-position-0-invalid-start-byte-dataset/87371 "2024-05-19T10:02:49Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![quhf](https://avatars.discourse-cdn.com/v4/letter/q/f04885/32.png) [@quhf](https://discuss.huggingface.co/u/quhf)\
**Post date:** [May 19, 2024, 10:02am UTC](https://discuss.huggingface.co/t/utf-8-codec-cant-decode-byte-0xff-in-position-0-invalid-start-byte-dataset/87371/1 "2024-05-19T10:02:50Z")

</div>

Hi! I’m trying to upload my own dataset I’ve generated.  
I’ve successfully generated the dataset and everytime I try to load the dataset, That error occurs and I don’t know how to fix it. Here’s the full error message.

Error code: FeaturesError  
Exception: UnicodeDecodeError  
Message: ‘utf-8’ codec can’t decode byte 0xff in position 0: invalid start byte  
Traceback: Traceback (most recent call last):  
File “/src/services/worker/src/worker/job\_runners/split/first\_rows.py”, line 323, in compute  
compute\_first\_rows\_from\_parquet\_response(  
File “/src/services/worker/src/worker/job\_runners/split/first\_rows.py”, line 88, in compute\_first\_rows\_from\_parquet\_response  
rows\_index = indexer.get\_rows\_index(  
File “/src/libs/libcommon/src/libcommon/parquet\_utils.py”, line 631, in get\_rows\_index  
return RowsIndex(  
File “/src/libs/libcommon/src/libcommon/parquet\_utils.py”, line 512, in **init**  
self.parquet\_index = self.\_init\_parquet\_index(  
File “/src/libs/libcommon/src/libcommon/parquet\_utils.py”, line 529, in \_init\_parquet\_index  
response = get\_previous\_step\_or\_raise(  
File “/src/libs/libcommon/src/libcommon/simple\_cache.py”, line 539, in get\_previous\_step\_or\_raise  
raise CachedArtifactError(  
libcommon.simple\_cache.CachedArtifactError: The previous step failed.

```
          During handling of the above exception, another exception occurred:
          
          Traceback (most recent call last):
            File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/packaged_modules/json/json.py", line 122, in _generate_tables
              pa_table = paj.read_json(
            File "pyarrow/_json.pyx", line 308, in pyarrow._json.read_json
            File "pyarrow/error.pxi", line 154, in pyarrow.lib.pyarrow_internal_check_status
            File "pyarrow/error.pxi", line 91, in pyarrow.lib.check_status
          pyarrow.lib.ArrowInvalid: JSON parse error: Invalid value. in row 0
          
          During handling of the above exception, another exception occurred:
          
          Traceback (most recent call last):
            File "/src/services/worker/src/worker/job_runners/split/first_rows.py", line 241, in compute_first_rows_from_streaming_response
              iterable_dataset = iterable_dataset._resolve_features()
            File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/iterable_dataset.py", line 2216, in _resolve_features
              features = _infer_features_from_batch(self.with_format(None)._head())
            File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/iterable_dataset.py", line 1239, in _head
              return _examples_to_batch(list(self.take(n)))
            File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/iterable_dataset.py", line 1389, in __iter__
              for key, example in ex_iterable:
            File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/iterable_dataset.py", line 1044, in __iter__
              yield from islice(self.ex_iterable, self.n)
            File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/iterable_dataset.py", line 282, in __iter__
              for key, pa_table in self.generate_tables_fn(**self.kwargs):
            File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/packaged_modules/json/json.py", line 145, in _generate_tables
              dataset = json.load(f)
            File "/usr/local/lib/python3.9/json/ __init__.py", line 293, in load
              return loads(fp.read(),
            File "/src/services/worker/.venv/lib/python3.9/site-packages/datasets/utils/file_utils.py", line 1101, in read_with_retries
              out = read(*args, **kwargs)
            File "/usr/local/lib/python3.9/codecs.py", line 322, in decode
              (result, consumed) = self._buffer_decode(data, self.errors, final)
          UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte

```