diff --git a/usr/lib/archboot/installer/blockdevices.sh b/usr/lib/archboot/installer/blockdevices.sh
index 9ba673fa6..011b2fc8e 100644
--- a/usr/lib/archboot/installer/blockdevices.sh
+++ b/usr/lib/archboot/installer/blockdevices.sh
@@ -396,7 +396,7 @@ _getavailpartitions()
 # the destination root partition last!
 _umountall()
 {
-    if [[ "${DESTDIR}" == "/install" && $(mountpoint -q ${DESTDIR}) ]]; then
+    if [[ "${DESTDIR}" == "/install" && mountpoint -q "${DESTDIR}" ]]; then
         swapoff -a >/dev/null 2>&1
         for i in $(findmnt --list --submounts "${DESTDIR}" -o TARGET -n | tac); do
             umount "$i"