diff --git a/public/biopet-tools-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/tools/BaseCounter.scala b/public/biopet-tools-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/tools/BaseCounter.scala
index 189525cf16b45aa2ddc9d39dd47112527dc25c3b..d15d26a368f25080e7c0e54f668a2af1b2831699 100644
--- a/public/biopet-tools-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/tools/BaseCounter.scala
+++ b/public/biopet-tools-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/tools/BaseCounter.scala
@@ -33,7 +33,6 @@ class BaseCounter(val root: Configurable) extends ToolCommandFunction {
   @Input(doc = "Bam File", required = true)
   var bamFile: File = _
 
-  @Output(doc = "Output directory", required = true)
   var outputDir: File = _
 
   var prefix: String = "output"