When UBT is launched through one of the standard wrapper scripts, Ctrl-C no longer cancels the build. The `dotnet UnrealBuildTool.dll` process and its compile actions keep running to completion in the background. UBT prints none of its usual cancellation output, and further Ctrl-C presses have no effect — the process tree has to be killed manually.
Steps to Reproduce
1. Linux, interactive terminal, source build of 5.8.1.
2. `Engine/Build/BatchFiles/RunUBT.sh UnrealEditor Linux Development`
3. Wait for compilation to start, press Ctrl-C.
4. UBT seems to ignore the command. `ps -ef | grep UnrealBuildTool` shows UBT still running.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-393319 in the post.
| 0 |
| Component | UE - Core - Cpp Tools - UnrealBuildTool |
|---|---|
| Affects Versions | 5.8 |
| Created | Aug 24, 2026 |
|---|---|
| Updated | Aug 26, 2026 |