# Build Error: Custom Module Appears in App but Build Exits with Code 1 (Slicer.rule and .rule Files)

**URL:** https://discourse.slicer.org/t/build-error-custom-module-appears-in-app-but-build-exits-with-code-1-slicer-rule-and-rule-files/43420
**Category:** Support
**Tags:** extensions-manager, python, module
**Created:** [June 19, 2025, 1:50pm UTC](https://discourse.slicer.org/t/build-error-custom-module-appears-in-app-but-build-exits-with-code-1-slicer-rule-and-rule-files/43420 "2025-06-19T13:50:05Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![software](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/software/32/79627_2.png) [@software](https://discourse.slicer.org/u/software)
#### Post date: [June 19, 2025, 1:50pm UTC](https://discourse.slicer.org/t/build-error-custom-module-appears-in-app-but-build-exits-with-code-1-slicer-rule-and-rule-files/43420/1 "2025-06-19T13:50:06Z")

</div>

**After integrating the custom modules into my Slicer-based application, I’m now getting the following error during the build process:**

Custom build for ‘E:\Safe\build\CMakeFiles\467e983c5e5c61d75f97be2c5e12c91e\Slicer-mkdir.rule;E:\Safe\build\CMakeFiles\467e983c5e5c61d75f97be2c5e12c91e\Slicer-download.rule;E:\Safe\build\CMakeFiles\467e983c5e5c61d75f97be2c5e12c91e\Slicer-update.rule;E:\Safe\build\CMakeFiles\467e983c5e5c61d75f97be2c5e12c91e\Slicer-patch.rule;E:\Safe\build\CMakeFiles\467e983c5e5c61d75f97be2c5e12c91e\Slicer-configure.rule;E:\Safe\build\CMakeFiles\467e983c5e5c61d75f97be2c5e12c91e\Slicer-build.rule;E:\Safe\build\CMakeFiles\467e983c5e5c61d75f97be2c5e12c91e\Slicer-forceconfigure.rule;E:\Safe\build\CMakeFiles\467e983c5e5c61d75f97be2c5e12c91e\Slicer-install.rule;E:\Safe\build\CMakeFiles\a4776f2d8ebb7610c206d34e471bef41\Slicer-complete.rule;E:\Safe\build\CMakeFiles\aa031ac59c12a6e617a2dfdd12069198\Slicer.rule;E:\Safe\build\slicersources-src\CMakeLists.txt’ exited with code 1.

**The custom module does appear correctly in the application after build, but this error shows up every time. Could you please suggest what might be causing this or how I can debug it?**

**Thank you!**