# Problem with "find\_bad\_channels\_maxwell"

**URL:** <https://mne.discourse.group/t/problem-with-find-bad-channels-maxwell/10713>\
**Category:** Support & Discussions\
**Tags:** preprocessing, maxwell-filter\
**Created:** [January 16, 2025, 6:39am UTC](https://mne.discourse.group/t/problem-with-find-bad-channels-maxwell/10713 "2025-01-16T06:39:43Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Yike](https://avatars.discourse-cdn.com/v4/letter/y/58f4c7/32.png) [@Yike](https://mne.discourse.group/u/Yike)\
**Post date:** [January 16, 2025, 6:39am UTC](https://mne.discourse.group/t/problem-with-find-bad-channels-maxwell/10713/1 "2025-01-16T06:39:43Z")

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> [@got stuck in mne.preprocessing.find\_bad\_channels\_maxwell()](https://mne.discourse.group/t/got-stuck-in-mne-preprocessing-find-bad-channels-maxwell/6614/1):
>
> ```python
> auto_noisy_chs, auto_flat_chs, auto_scores = mne.preprocessing.find_bad_channels_maxwell(
> raw, return_scores=True, verbose=True)
> 
> ```

I use maxwell to detect bad channel for MEG data, but got this error:Number of requested bases (95) exceeds number of good sensors (63). How to solve this problem?

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**Author:** ![wmvanvliet](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/wmvanvliet/32/100_2.png) [@wmvanvliet](https://mne.discourse.group/u/wmvanvliet)\
**Post date:** [January 16, 2025, 7:43am UTC](https://mne.discourse.group/t/problem-with-find-bad-channels-maxwell/10713/2 "2025-01-16T07:43:34Z")

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What MEG system are you using? Having only 63 good channels seems like an odd number to me.