diff --git a/Foundation/Process.swift b/Foundation/Process.swift
index 500a53123b..153e264f54 100644
--- a/Foundation/Process.swift
+++ b/Foundation/Process.swift
@@ -1128,6 +1128,7 @@ open class Process: NSObject {
         } while( self.isRunning == true && RunLoop.current.run(mode: .default, before: Date(timeIntervalSinceNow: 0.05)) )
         
         self.runLoop = nil
+        self.runLoopSource = nil
     }
 }