Java Unreal Engine 5.4 builds are canceled for no apparent reason

Symptoms

Java Unreal Engine 5.4 builds are abruptly canceled, or the build agent is terminated for no apparent reason.

Cause

Unreal Engine 5.4 introduced a new "cleanup tool" in UEDeployAndroid.cs which force kills the remaining Java processes by executing the cmd.exe /c taskkill.exe /F /IM java.exe /T command. This behavior is not present in Unreal Engine 5.2.

This command finds all processes that match the java.exe image specified in the /IM flag. Since a TeamCity agent is also a Java process, the command terminates the agent along with the residing build processes (e.g., Gradle). This results in an abrupt build cancellation. The build is then re-added to the queue in TeamCity.

Resolution

This behavior can be disabled in the Unreal Engine settings. See UEDeployAndroid.cs