diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index 3ce80bf67..91679a79d 100755
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -243,7 +243,7 @@ object Defaults extends BuildCommon {
       },
       trapExit :== true,
       connectInput :== false,
-      cancelable :== false,
+      cancelable :== true,
       taskCancelStrategy := { state: State =>
         if (cancelable.value) TaskCancellationStrategy.Signal
         else TaskCancellationStrategy.Null