diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index 693eef0fa..87e3f9831 100644
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -342,9 +342,10 @@ object Defaults extends BuildCommon {
   ))
 
   lazy val projectTasks: Seq[Setting[_]] = Seq(
-    cleanFiles := cleanFilesTask.value,
+    cleanFiles := Seq(managedDirectory.value, target.value),
+    cleanFilesTask := cleanFilesImpl.value,
     cleanKeepFiles := historyPath.value.toVector,
-    clean := (Def.task { IO.delete(cleanFiles.value) } tag (Tags.Clean)).value,
+    clean := (Def.task { IO.delete(cleanFilesTask.value) } tag (Tags.Clean)).value,
     consoleProject := consoleProjectTask.value,
     watchTransitiveSources := watchTransitiveSourcesTask.value,
     watch := watchSetting.value
@@ -780,8 +781,8 @@ object Defaults extends BuildCommon {
     pickMainClass(classes)
   }
 
-  /** Implements `cleanFiles` task. */
-  def cleanFilesTask: Initialize[Task[Vector[File]]] =
+  /** Implements `cleanFilesTask` */
+  def cleanFilesImpl: Initialize[Task[Vector[File]]] =
     Def.task {
       val filesAndDirs = Vector(managedDirectory.value, target.value)
       val preserve = cleanKeepFiles.value
diff --git a/main/src/main/scala/sbt/Keys.scala b/main/src/main/scala/sbt/Keys.scala
index 789517c3e..4254e28c7 100644
--- a/main/src/main/scala/sbt/Keys.scala
+++ b/main/src/main/scala/sbt/Keys.scala
@@ -107,7 +107,8 @@ object Keys {
   val classDirectory = SettingKey[File]("class-directory", "Directory for compiled classes and copied resources.", AMinusSetting)
   @deprecated("Use the cacheDirectory provided by streams.", "0.13.0")
   val cacheDirectory = SettingKey[File]("cache-directory", "Directory used for caching task data.", BMinusSetting)
-  val cleanFiles = TaskKey[Seq[File]]("clean-files", "The files to recursively delete during a clean.", BSetting)
+  val cleanFiles = SettingKey[Seq[File]]("clean-files", "The files to recursively delete during a clean.", BSetting)
+  val cleanFilesTask = TaskKey[Seq[File]]("clean-files-task", "The files to recursively delete during a clean.", BSetting)
   val cleanKeepFiles = SettingKey[Seq[File]]("clean-keep-files", "Files or directories to keep during a clean. Must be direct children of target.", CSetting)
   val crossPaths = SettingKey[Boolean]("cross-paths", "If true, enables cross paths, which distinguish input and output directories for cross-building.", ASetting)
   val taskTemporaryDirectory = SettingKey[File]("task-temporary-directory", "Directory used for temporary files for tasks that is deleted after each task execution.", DSetting)