diff --git a/macos-guest-virtualbox.sh b/macos-guest-virtualbox.sh
index 4c91e61..03d0383 100755
--- a/macos-guest-virtualbox.sh
+++ b/macos-guest-virtualbox.sh
@@ -343,7 +343,7 @@ else
 fi
 
 # dmg2img
-if [[ -z "$(dmg2img -d 2>/dev/null)" ]]; then
+if ! dmg2img >/dev/null 2>&1; then
     if [[ -z "$(cygcheck -V 2>/dev/null)" ]]; then
         echo "Please install the package dmg2img."
         exit