Sandboxing is a protective technology in macOS that is used for all applications downloaded from the App Store. While normally helpful, it can make some tasks more difficult including running some applications such as compilers.
If you need to perform these tasks from SciTE then the non-sandboxed version of SciTE may be used.
To install SciTEUnboxed:
This is currently being beta tested and may have problems.
SciTEUnboxed will not run unless it can find the corresponding version of SciTE.
Always back up every release of SciTE that you want to use with SciTEUnboxed. There may not be a release of SciTEUnboxed for every release of SciTE and you may need to reinstall SciTE if there is a disk failure or a newer version of SciTE is installed.
The directories used by SciTE and SciTEUnboxed are different with SciTE's located in ~/Library/Containers/org.scintilla.SciTE and SciTEUnboxed's located in ~/Library/Application Support/org.scintilla.SciTE.