# Error with dwipreproc

**URL:** https://community.mrtrix.org/t/error-with-dwipreproc/982
**Category:** Uncategorized
**Created:** [June 19, 2017, 1:32pm UTC](https://community.mrtrix.org/t/error-with-dwipreproc/982 "2017-06-19T13:32:31Z")
**Posts on this page:** 1
**Showing post:** 8

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### Author: ![jdtournier](https://community.mrtrix.org/user_avatar/community.mrtrix.org/jdtournier/32/2594_2.png) [@jdtournier](https://community.mrtrix.org/u/jdtournier)
#### Post date: [November 20, 2018, 4:43pm UTC](https://community.mrtrix.org/t/error-with-dwipreproc/982/8 "2018-11-20T16:43:18Z")

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> [@Yixin\_Ma](#):
>
> But it takes forever to run the code. (More than 12 hours, does it mean that I miss some parameters and make it unable to converge?)

This might be due to there being lots of _b_=0 images, which `topup` takes ages to process – see [this recent thread](https://community.mrtrix.org/t/dwipreproc-topup-with-many-b0-up-down-reverse-phase-pairs/2047) on this issue.

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