# SlicerRT DRR generation module does not work well on macbook

**URL:** <https://discourse.slicer.org/t/slicerrt-drr-generation-module-does-not-work-well-on-macbook/26022>\
**Category:** Support\
**Created:** [November 2, 2022, 7:44am UTC](https://discourse.slicer.org/t/slicerrt-drr-generation-module-does-not-work-well-on-macbook/26022 "2022-11-02T07:44:59Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![jamesobutler](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/jamesobutler/32/7511_2.png) [@jamesobutler](https://discourse.slicer.org/u/jamesobutler)\
**Post date:** [November 2, 2022, 12:08pm UTC](https://discourse.slicer.org/t/slicerrt-drr-generation-module-does-not-work-well-on-macbook/26022/2 "2022-11-02T12:08:35Z")

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Are you observing the same error on macOS as you mentioned on your previous thread:

> [@Errors when using DRR Generator](https://discourse.slicer.org/t/errors-when-using-drr-generator/25448):
>
> Operating system: Mac OS system Slicer version: Slice 5.0.3 Expected behavior: When I using DRR Generator tool, there is always an error occurred! The error message is : " The message detail is: Exception thrown in event: /Volumes/D/S/S-0-build/ITK/Modules/IO/NRRD/src/itkNrrdImageIO.cxx:1118: ITK ERROR: NrrdImageIO(0x7f96d87621b0): Write: Error writing output\_fixed.nrrd: [nrrd] nrrdSave: couldn’t fopen(“output\_fixed.nrrd”,“wb”): Read-only file system" Is there anyone else met this error b…

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