diff --git a/tasks/standard/Streams.scala b/tasks/standard/Streams.scala
index 838a53f6d..d92ea34a5 100644
--- a/tasks/standard/Streams.scala
+++ b/tasks/standard/Streams.scala
@@ -86,7 +86,7 @@ object Streams
 			def make[T <: Closeable](a: Key, sid: String)(f: File => T): T = synchronized {
 				checkOpen()
 				val file = taskDirectory(a) / sid
-				IO.touch(file)
+				IO.touch(file, false)
 				val t = f( file )
 				opened ::= t
 				t
diff --git a/util/io/IO.scala b/util/io/IO.scala
index 024de0375..d8dc89584 100644
--- a/util/io/IO.scala
+++ b/util/io/IO.scala
@@ -70,15 +70,15 @@ object IO
 			(name, "")
 	}
 
-	def touch(files: Traversable[File]): Unit = files.foreach(touch)
+	def touch(files: Traversable[File]): Unit = files.foreach(f => touch(f))
 	/** Creates a file at the given location.*/
-	def touch(file: File)
+	def touch(file: File, setModified: Boolean = true)
 	{
 		createDirectory(file.getParentFile)
 		val created = translate("Could not create file " + file) { file.createNewFile() }
 		if(created || file.isDirectory)
 			()
-		else if(!file.setLastModified(System.currentTimeMillis))
+		else if(setModified && !file.setLastModified(System.currentTimeMillis))
 			error("Could not update last modified time for file " + file)
 	}
 	def createDirectories(dirs: Traversable[File]): Unit =