diff --git a/b9.cabal b/b9.cabal
--- a/b9.cabal
+++ b/b9.cabal
@@ -1,5 +1,5 @@
 name:                b9
-version:             0.5.15
+version:             0.5.16
 
 synopsis:            A tool and library for building virtual machine images.
 
diff --git a/src/lib/B9/DiskImageBuilder.hs b/src/lib/B9/DiskImageBuilder.hs
--- a/src/lib/B9/DiskImageBuilder.hs
+++ b/src/lib/B9/DiskImageBuilder.hs
@@ -252,7 +252,7 @@
           (Raw,Ext4) -> do
               let fsCmd = "mkfs.ext4"
               dbgL (printf "Creating file system %s" (show imgFs))
-              cmd (printf "%s -L '%s' -q '%s'" fsCmd fsLabel imgFile)
+              cmd (printf "%s -F -L '%s' -q '%s'" fsCmd fsLabel imgFile)
           (it,fs) ->
               error
                   (printf