diff --git a/src/mergerfs.cpp b/src/mergerfs.cpp
index dcfaac75..8bcf13d9 100644
--- a/src/mergerfs.cpp
+++ b/src/mergerfs.cpp
@@ -410,6 +410,7 @@ main(int    argc_,
     ;
 
   app.add_option("mountpoint")
+    ->default_val("")
     ->required()
     ;