# Error with DiffusionQC module (GradQC)

**URL:** <https://discourse.slicer.org/t/error-with-diffusionqc-module-gradqc/17330>\
**Category:** Support\
**Tags:** diffusion\
**Created:** [April 26, 2021, 12:31pm UTC](https://discourse.slicer.org/t/error-with-diffusionqc-module-gradqc/17330 "2021-04-26T12:31:45Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![amvoid](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/amvoid/32/10795_2.png) [@amvoid](https://discourse.slicer.org/u/amvoid)\
**Post date:** [April 26, 2021, 12:31pm UTC](https://discourse.slicer.org/t/error-with-diffusionqc-module-gradqc/17330/1 "2021-04-26T12:31:45Z")

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Operating system: win10/Ubuntu 20  
Slicer version: 4.11

After I install DiffusionQC extension, there come out an error whenever I star Slicer. I notice that GradQC failed to install, but I don’t know why.

Traceback (most recent call last):  
File “”, line 1, in   
File “C:\Users\Henry\AppData\Local\NA-MIC\Slicer 4.11.20210226\lib\Python\Lib\imp.py”, line 170, in load\_source  
module = \_exec(spec, sys.modules[name])  
File “”, line 618, in \_exec  
File “”, line 678, in exec\_module  
File “”, line 219, in \_call\_with\_frames\_removed  
File “C:/Users/Henry/AppData/Local/NA-MIC/Slicer 4.11.20210226/NA-MIC/Extensions-29738/DiffusionQC/lib/Slicer-4.11/qt-scripted-modules/GradQC.py”, line 5, in   
from gradqclib.slicerUserInteraction import slicerGUI  
File “C:\Users\Henry\AppData\Local\NA-MIC\Slicer 4.11.20210226\NA-MIC\Extensions-29738\DiffusionQC\lib\Slicer-4.11\qt-scripted-modules\gradqclib\slicerUserInteraction.py”, line 6, in   
from diffusionqclib.dwi\_attributes import dwi\_attributes  
File “C:\Users\Henry\AppData\Local\NA-MIC\Slicer 4.11.20210226\NA-MIC\Extensions-29738\DiffusionQC\Lib\site-packages\diffusionqclib\dwi\_attributes.py”, line 4, in   
from nhdr\_write import nhdr\_write  
ModuleNotFoundError: No module named ‘nhdr\_write’

And the same problem happend in Ubuntu system.

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [April 26, 2021, 11:20pm UTC](https://discourse.slicer.org/t/error-with-diffusionqc-module-gradqc/17330/2 "2021-04-26T23:20:05Z")

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I’m not sure if DiffusionQC extension developers monitor the Slicer forum, so it could be useful to report the problem at their issue tracker. Please copy here the link to the bug report.

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**Author:** ![amvoid](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/amvoid/32/10795_2.png) [@amvoid](https://discourse.slicer.org/u/amvoid)\
**Post date:** [April 27, 2021, 1:58am UTC](https://discourse.slicer.org/t/error-with-diffusionqc-module-gradqc/17330/3 "2021-04-27T01:58:58Z")

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[Fail to instantiate module “GradQC” with Slicer 4.11 · Issue #46 · pnlbwh/SlicerDiffusionQC (github.com)](https://github.com/pnlbwh/SlicerDiffusionQC/issues/46#38)

[Relative import necessary for Slicer-4.11 · Issue #42 · pnlbwh/SlicerDiffusionQC (github.com)](https://github.com/pnlbwh/SlicerDiffusionQC/issues/42)

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<div class="post-metadata">

**Author:** ![amvoid](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/amvoid/32/10795_2.png) [@amvoid](https://discourse.slicer.org/u/amvoid)\
**Post date:** [April 27, 2021, 3:14am UTC](https://discourse.slicer.org/t/error-with-diffusionqc-module-gradqc/17330/4 "2021-04-27T03:14:11Z")

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There are some changes in version 4.11 and DiffusionQC don’t match the new version. I reinstalled version 4.10, but didn’t find the extension at all in Extensions Manager. Weird…

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [May 1, 2021, 2:23pm UTC](https://discourse.slicer.org/t/error-with-diffusionqc-module-gradqc/17330/5 "2021-05-01T14:23:55Z")

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You cannot use extensions that are built for Slicer with a different major or minor version. Thanks for including links to the bug reports, I can see that you are working with the developer to resolve the issues.