diff --git a/Volume.h b/Volume.h
index 7306e4e..9bf0f0a 100644
--- a/Volume.h
+++ b/Volume.h
@@ -53,7 +53,7 @@
     virtual ~Volume();
 
     int mountVol();
-    int unmountVol();
+    int unmountVol(bool force);
     int formatVol();
 
     const char *getLabel() { return mLabel; }