diff --git a/build-windows-base.sh b/build-windows-base.sh
index 2023d0b..02b597e 100755
--- a/build-windows-base.sh
+++ b/build-windows-base.sh
@@ -126,9 +126,9 @@ fi
 if [[ -z "${WIN11_VM_INSTALL_ISO:-}" ]] && ! "$downloader" --print-path windows11 --iso >/dev/null 2>&1; then
   "$downloader" --print-path windows11 --iso >&2 || true
   if { : </dev/tty >/dev/tty; } 2>/dev/null; then
-    printf 'Download the Windows 11 ISO now? [y/N] ' >/dev/tty
+    printf 'Download the Windows 11 ISO now? [Y/n] ' >/dev/tty
     read -r answer </dev/tty || answer=
-    [[ "$answer" == [yY] || "$answer" == [yY][eE][sS] ]] || exit 1
+    [[ -z "$answer" || "$answer" == [yY] || "$answer" == [yY][eE][sS] ]] || exit 1
     "$downloader" windows11 || exit 1
   fi
 fi
diff --git a/download-images.sh b/download-images.sh
index 8d9379c..2ffa965 100755
--- a/download-images.sh
+++ b/download-images.sh
@@ -157,13 +157,13 @@ EOF
 }
 
 # Ask a yes/no question on the terminal; fails when there is none or the answer
-# is not yes. stdout carries the printed path, so all dialogue goes to /dev/tty.
+# is not yes (an empty answer means yes). stdout carries the printed path, so all dialogue goes to /dev/tty.
 ask_yes_no() {
   local answer
   { : </dev/tty >/dev/tty; } 2>/dev/null || return 1
-  printf '%s [y/N] ' "$1" >/dev/tty
+  printf '%s [Y/n] ' "$1" >/dev/tty
   read -r answer </dev/tty || return 1
-  [[ "$answer" == [yY] || "$answer" == [yY][eE][sS] ]]
+  [[ -z "$answer" || "$answer" == [yY] || "$answer" == [yY][eE][sS] ]]
 }
 
 # Print the base QCOW2 path. When the image does not exist and a terminal is