# Issue with Installing Extensions in Slicer Custom App
**URL:** https://discourse.slicer.org/t/issue-with-installing-extensions-in-slicer-custom-app/42214
**Category:** Support
**Created:** [March 19, 2025, 7:01am UTC](https://discourse.slicer.org/t/issue-with-installing-extensions-in-slicer-custom-app/42214 "2025-03-19T07:01:51Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@software](https://discourse.slicer.org/u/software)
#### Post date: [March 19, 2025, 7:01am UTC](https://discourse.slicer.org/t/issue-with-installing-extensions-in-slicer-custom-app/42214/1 "2025-03-19T07:01:52Z")
I turned **Slicer\_BUILD\_EXTENSIONMANAGER\_SUPPORT** ON in the top-level `CMakeLists.txt`, then configured and generated the project using CMake GUI. After that, I opened the project from CMake GUI in Visual Studio and built _All Build_ in the `SlicerCustomAppTemplate`, as I wanted to download some extensions.
I tried installing the _HD Brain Extraction Tool_ extension. I even received a pop-up notification at the top right of the screen saying _“Installed Extension: HD Brain Extraction Tool.”_ However, the restart button at the bottom right corner of the screen does not get activated.
When I manually close and reopen Slicer, I cannot find the extension anywhere.
Has anyone encountered this issue before? Any help or guidance would be greatly appreciated!
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### Author:  [@pieper](https://discourse.slicer.org/u/pieper)
#### Post date: [March 19, 2025, 1:25pm UTC](https://discourse.slicer.org/t/issue-with-installing-extensions-in-slicer-custom-app/42214/2 "2025-03-19T13:25:50Z")
Check the application log. It’s very unlikely that extensions built for the regular Slicer will work in a custom app because of compilation differences.
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### Author:  [@software](https://discourse.slicer.org/u/software)
#### Post date: [March 19, 2025, 6:58pm UTC](https://discourse.slicer.org/t/issue-with-installing-extensions-in-slicer-custom-app/42214/3 "2025-03-19T18:58:10Z")
First of all, thanks for the reply.i have another question sir plz guide me
I have built a **custom template of Kitware** in **Release mode** using **CMake GUI** with the following directories:
- **Source code:** `E:/Safe`
- **Binary build:** `E:/Safe/build`
After configuring and generating the project, the build was successful. Now, I have two **.sln** files:
1. `build/safe.sln`
2. `build/slicer_build/slicer.sln`
I am confused about which **.sln** file I should open in **Visual Studio** to continue compiling and customizing 3D Slicer.