# Errors when using DRR Generator
**URL:** https://discourse.slicer.org/t/errors-when-using-drr-generator/25448
**Category:** Support
**Tags:** extensions-manager
**Created:** [September 27, 2022, 2:26pm UTC](https://discourse.slicer.org/t/errors-when-using-drr-generator/25448 "2022-09-27T14:26:54Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@suzume](https://discourse.slicer.org/u/suzume)
#### Post date: [September 27, 2022, 2:26pm UTC](https://discourse.slicer.org/t/errors-when-using-drr-generator/25448/1 "2022-09-27T14:26:54Z")
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 before? Could you please tell me how to fix it?
---
### Author:  [@pieper](https://discourse.slicer.org/u/pieper)
#### Post date: [September 27, 2022, 7:32pm UTC](https://discourse.slicer.org/t/errors-when-using-drr-generator/25448/2 "2022-09-27T19:32:06Z")
> [@suzume](#):
>
> Read-only file system
You don’t have permission to save in the indicated location.
It looks like this name [is hard coded in the DRRGenerator](https://github.com/lancelevine/SlicerDRRGenerator/blob/6ac5f40e0655dfd34437055d8c3bc98b278053a0/DRRGeneratorModule/qSlicerDRRGeneratorModuleModuleWidget.cxx#L527). If you launch slicer from a terminal in a directory where you have write permission you should be able to make it work. You could file [an issue](https://github.com/lancelevine/SlicerDRRGenerator/issues) to alert the developers of this problem.
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### Author:  [@suzume](https://discourse.slicer.org/u/suzume)
#### Post date: [September 28, 2022, 3:00am UTC](https://discourse.slicer.org/t/errors-when-using-drr-generator/25448/4 "2022-09-28T03:00:57Z")
Thanks for your reply! I re-installed the 3D slicer and the DRR Generator on Windows system. The error was fixed. It seems that the error occurred because of the Mac OS system.