diff --git a/scripts/create-darwin-volume.sh b/scripts/create-darwin-volume.sh
index f3e0d46f1..d6fb44f43 100755
--- a/scripts/create-darwin-volume.sh
+++ b/scripts/create-darwin-volume.sh
@@ -1,8 +1,8 @@
 #!/bin/sh
 set -e
 
-root_disks() {
-    diskutil list -plist /
+root_disk() {
+    diskutil info -plist /
 }
 
 apfs_volumes_for() {
@@ -11,7 +11,7 @@ apfs_volumes_for() {
 }
 
 disk_identifier() {
-    xpath "/plist/dict/key[text()='WholeDisks']/following-sibling::array[1]/string/text()" 2>/dev/null
+    xpath "/plist/dict/key[text()='ParentWholeDisk']/following-sibling::string[1]/text()" 2>/dev/null
 }
 
 volume_get() {
@@ -81,7 +81,7 @@ main() {
         sudo mkdir /nix
     fi
 
-    disk=$(root_disks | disk_identifier)
+    disk=$(root_disk | disk_identifier)
     volume=$(find_nix_volume "$disk")
     if [ -z "$volume" ]; then
         echo "Creating a Nix Store volume..." >&2
diff --git a/scripts/install-nix-from-closure.sh b/scripts/install-nix-from-closure.sh
index 88275d1f0..7d32bf92e 100644
--- a/scripts/install-nix-from-closure.sh
+++ b/scripts/install-nix-from-closure.sh
@@ -91,9 +91,22 @@ while [ $# -gt 0 ]; do
     shift
 done
 
-if [ "$(uname -s)" = "Darwin" ] && [ "$CREATE_DARWIN_VOLUME" = 1 ]; then
-    printf '\e[1;31mCreating volume and mountpoint /nix.\e[0m\n'
-    "$self/create-darwin-volume.sh"
+if [ "$(uname -s)" = "Darwin" ]; then
+    if [ "$CREATE_DARWIN_VOLUME" = 1 ]; then
+        printf '\e[1;31mCreating volume and mountpoint /nix.\e[0m\n'
+        "$self/create-darwin-volume.sh"
+    fi
+
+    info=$(diskutil info -plist / | xpath "/plist/dict/key[text()='Writable']/following-sibling::true[1]" 2> /dev/null)
+    if ! [ -e $dest ] && [ -n "$info" ]; then
+        (
+            echo ""
+            echo "Installing on macOS >=10.15 requires relocating the store to an apfs volume."
+            echo "Use --create-volume or run the preparation steps manually."
+            echo "See https://nixos.org/nix/manual/#sect-darwin-apfs-volume."
+            echo ""
+        ) >&2
+    fi
 fi
 
 if [ "$INSTALL_MODE" = "daemon" ]; then
@@ -113,15 +126,6 @@ if ! [ -e $dest ]; then
     echo "directory $dest does not exist; creating it by running '$cmd' using sudo" >&2
     if ! sudo sh -c "$cmd"; then
         echo "$0: please manually run '$cmd' as root to create $dest" >&2
-        if [ "$(uname -s)" = "Darwin" ]; then
-            (
-                echo ""
-                echo "Installing on macOS >=10.15 requires relocating the store to an apfs volume."
-                echo "Use --create-volume or run the preparation steps manually."
-                echo "See https://nixos.org/nix/manual/#sect-darwin-apfs-volume."
-                echo ""
-            ) >&2
-        fi
         exit 1
     fi
 fi