On Windows 7 and Windows 10, this failed to close external process. But it works with commit https://github.com/gcnagel/JobObject.Net/commit/ec54170ce5065ea5f9be14211ba5f729a9ec2010 Clearly, this pull request is relevant in my experience: https://github.com/jmderuty/JobObject.Net/pull/1 Thank you for your attention.