Hi,

We are using QB v12.0.27, and are seeing a weird bug when cancelling a process on a windows host.

Command error output: ERROR: The process with PID 9060 (child process of PID 7684) could not be terminated.
    Reason: There is no running instance of the task.
        at com.pmease.quickbuild.execution.Commandline$ExecuteResult.buildException(Commandline.java:517)
        at com.pmease.quickbuild.execution.Commandline$ExecuteResult.checkReturnCode(Commandline.java:531)
        at org.jvnet.winp.WinProcess.killRecursively(WinProcess.java:74)
        at com.pmease.quickbuild.execution.killtree.ProcessTree$Windows$1.killRecursively(ProcessTree.java:345)
        at com.pmease.quickbuild.execution.killtree.ProcessTree$Windows.killAll(ProcessTree.java:399)
        at com.pmease.quickbuild.execution.killtree.ProcessTree.killAll(ProcessTree.java:148)
        at com.pmease.quickbuild.execution.Commandline.terminateProcessTree(Commandline.java:431)

When looking on the host using sysinternals process explorer, no running process with that PID exists. It seems like this is a pretty serious bug where, if the process kill fails due to "not existing" it should trap that exception and consider that as a success. The current behavior results in this permanently hangs the build job. The only way past this is to force restart the build agent service.

Please file this and let me know when you have a solution.