Week 4 Face recognition Grader Failure

Error after submitting assignment.

[ValidateApp | INFO] Validating ‘/home/jovyan/work/submitted/courseraLearner/W4A1/Face_Recognition.ipynb’
[ValidateApp | ERROR] Traceback (most recent call last):
File “/opt/conda/lib/python3.7/site-packages/nbgrader/preprocessors/checkcellmetadata.py”, line 11, in preprocess
File “/opt/conda/lib/python3.7/site-packages/nbgrader/nbgraderformat/v3.py”, line 107, in validate_nb
raise ValidationError(“Duplicate grade id: {}”.format(grade_id))
jsonschema.exceptions.ValidationError: Duplicate grade id: cell-ba2f317e79e15a2f

[ValidateApp | ERROR] Notebook failed to validate; the nbgrader metadata may be corrupted.
[ValidateApp | ERROR] Traceback (most recent call last):
File “/opt/conda/lib/python3.7/site-packages/nbgrader/apps/validateapp.py”, line 72, in start
File “/opt/conda/lib/python3.7/site-packages/nbgrader/validator.py”, line 340, in validate_and_print
results = self.validate(filename)
File “/opt/conda/lib/python3.7/site-packages/nbgrader/validator.py”, line 311, in validate
nb = self._preprocess(nb)
File “/opt/conda/lib/python3.7/site-packages/nbgrader/validator.py”, line 290, in _preprocess
nb, resources = pp.preprocess(nb, resources)
File “/opt/conda/lib/python3.7/site-packages/nbgrader/preprocessors/checkcellmetadata.py”, line 16, in preprocess
raise ValidationError(msg)
jsonschema.exceptions.ValidationError: Notebook failed to validate; the nbgrader metadata may be corrupted.

[ValidateApp | ERROR] nbgrader encountered a fatal error while trying to validate ‘submitted/courseraLearner/W4A1/Face_Recognition.ipynb’

Hello Mentors,


Could you please help me out, I feel there is some issue in grader and its failing.

I’m stuck totally and cannot proceed further.

I know you all barely get time to look at issues but please spare some time and look into this issue.


It looks like there is something wrong with your notebook. The error messages sound like perhaps you’ve accidentally duplicated one of the graded cells. My suggestion would be to use the “Get a Fresh Copy” procedure documented on the FAQ Thread. Rename your current notebook first, of course. Then very carefully “copy/paste” over just your completed code segments to the clean copy and then try the grader again. Please give that a try and let us know whether that solves the problem or not.

1 Like

Hi Mentor,

Really appreciate you for responding with accurate solution.

Issue has gone.

Thankyou so much :slight_smile:

Hi, @Shubhamg. That’s great news! Thank you for confirming the results of your experiment. We’re all learning how the new graders work, so it helps us to gather this kind of real world experience.