# Build Error & CustomSlicer's Purpose

**URL:** <https://discourse.slicer.org/t/build-error-customslicers-purpose/29910>\
**Category:** Development\
**Tags:** python\
**Created:** [June 8, 2023, 6:34am UTC](https://discourse.slicer.org/t/build-error-customslicers-purpose/29910 "2023-06-08T06:34:27Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![dsa934](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/dsa934/32/17907_2.png) [@dsa934](https://discourse.slicer.org/u/dsa934)\
**Post date:** [June 8, 2023, 6:34am UTC](https://discourse.slicer.org/t/build-error-customslicers-purpose/29910/1 "2023-06-08T06:34:27Z")

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Operating system: window 10  
Slicer version: 5.2.1

Hi all,

![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/6/3/63bf0ceac89a0a45826fb0c9e4aefbfad8537eb4.png)

Q1. When the Cmake → build process was performed for each of three slicer5.2.1, slicer5.2.2, and CustomSlicer, the same permission error for the vtk folder occurred. What to do in this case?

Q2. I’ve heard that CustomSlicer allows you to customize many things without changing the slicer’s core, but is the ‘many’ mentioned here only about the GUI?

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<div class="post-metadata">

**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:** [June 16, 2023, 2:59pm UTC](https://discourse.slicer.org/t/build-error-customslicers-purpose/29910/2 "2023-06-16T14:59:42Z")

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The build tree does not look similar to what you get by following the build instructions, so we cannot even guess what could cause the write permission issue.

You can customize complete behavior of Slicer in a custom application, not just the GUI.