# Dwinormalise output file error **URL:** \ **Category:** Uncategorized\ **Created:** [July 4, 2019, 2:23pm UTC](https://community.mrtrix.org/t/dwinormalise-output-file-error/2642 "2019-07-04T14:23:42Z")\ **Posts on this page:** 1\ **Showing post:** 2
**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:** [July 11, 2019, 10:24am UTC](https://community.mrtrix.org/t/dwinormalise-output-file-error/2642/2 "2019-07-11T10:24:02Z")
> [@DaqiangKe](#): > > There are no b=0 volumes in my file. It is the reason caused the problem? I’ve just looked at the code for this, and yes, that would be the reason. As it says in the [command synopsis](https://mrtrix.readthedocs.io/en/latest/reference/commands/dwinormalise.html#synopsis), it [looks for b=0 volumes](https://github.com/MRtrix3/mrtrix3/blob/master/cmd/dwinormalise.cpp#L71-L72), then [computes the mean b=0 intensity for each voxel in the mask](https://github.com/MRtrix3/mrtrix3/blob/master/cmd/dwinormalise.cpp#L82-L87), which will give Not-a-Number due to the divide by zero. More to the point though: these days we would advocate the use of mtnormalise to deal with both intensity normalisation and bias field correction – even for single-shell data where we’d advocate the use of multi-tissue CSD with WM & CSF responses only (see e.g. [this post](http://community.mrtrix.org/t/fixel-based-analysis-on-single-shell-data/897/8), amongst others). I think we’ll eventually end up removing `dwinormalise` altogether… --- _[View the full topic](https://community.mrtrix.org/t/dwinormalise-output-file-error/2642)._