diff --git a/tools/test/stress2/misc/msdos12.sh b/tools/test/stress2/misc/msdos12.sh
index 8e3984305cd..e34c26046a9 100755
--- a/tools/test/stress2/misc/msdos12.sh
+++ b/tools/test/stress2/misc/msdos12.sh
@@ -44,7 +44,7 @@ gpart create -s bsd md$mdstart > /dev/null
 gpart add -t freebsd-ufs md$mdstart > /dev/null
 part=a
 newfs_msdos -F 32 -b 8192 /dev/md$mdstart$part > /dev/null
-mount -t msdosfs /dev/md$mdstart$part $mntpoint
+mount -t msdosfs -o "-u$testuser" /dev/md$mdstart$part $mntpoint
 mkdir $mntpoint/stressX
 chmod 0777 $mntpoint/stressX
 set +e