diff --git a/test/units/TEST-13-NSPAWN.nspawn.sh b/test/units/TEST-13-NSPAWN.nspawn.sh
index 2bd3962ffb..13dc1acdb3 100755
--- a/test/units/TEST-13-NSPAWN.nspawn.sh
+++ b/test/units/TEST-13-NSPAWN.nspawn.sh
@@ -90,45 +90,50 @@ testcase_sanity() {
     # --template=
     root="$(mktemp -u -d /var/lib/machines/TEST-13-NSPAWN.sanity.XXX)"
     coverage_create_nspawn_dropin "$root"
-    (! systemd-nspawn --directory="$root" bash -xec 'echo hello')
+    (! systemd-nspawn --register=no --directory="$root" bash -xec 'echo hello')
     # Initialize $root from $template (the $root directory must not exist, hence
     # the `mktemp -u` above)
-    systemd-nspawn --directory="$root" --template="$template" bash -xec 'echo hello'
-    systemd-nspawn --directory="$root" bash -xec 'echo hello; touch /initialized'
+    systemd-nspawn --register=no --directory="$root" --template="$template" bash -xec 'echo hello'
+    systemd-nspawn --register=no --directory="$root" bash -xec 'echo hello; touch /initialized'
     test -e "$root/initialized"
     # Check if the $root doesn't get re-initialized once it's not empty
-    systemd-nspawn --directory="$root" --template="$template" bash -xec 'echo hello'
+    systemd-nspawn --register=no --directory="$root" --template="$template" bash -xec 'echo hello'
     test -e "$root/initialized"
 
-    systemd-nspawn --directory="$root" --ephemeral bash -xec 'touch /ephemeral'
+    systemd-nspawn --register=no --directory="$root" --ephemeral bash -xec 'touch /ephemeral'
     test ! -e "$root/ephemeral"
-    (! systemd-nspawn --directory="$root" \
+    (! systemd-nspawn --register=no \
+                      --directory="$root" \
                       --read-only \
                       bash -xec 'touch /nope')
     test ! -e "$root/nope"
-    systemd-nspawn --image="$image" bash -xec 'echo hello'
+    systemd-nspawn --register=no --image="$image" bash -xec 'echo hello'
 
     # --volatile=
     touch "$root/usr/has-usr"
     # volatile(=yes): rootfs is tmpfs, /usr/ from the OS tree is mounted read only
-    systemd-nspawn --directory="$root"\
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --volatile \
                    bash -xec 'test -e /usr/has-usr; touch /usr/read-only && exit 1; touch /nope'
     test ! -e "$root/nope"
     test ! -e "$root/usr/read-only"
-    systemd-nspawn --directory="$root"\
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --volatile=yes \
                    bash -xec 'test -e /usr/has-usr; touch /usr/read-only && exit 1; touch /nope'
     test ! -e "$root/nope"
     test ! -e "$root/usr/read-only"
     # volatile=state: rootfs is read-only, /var/ is tmpfs
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --volatile=state \
                    bash -xec 'test -e /usr/has-usr; mountpoint /var; touch /read-only && exit 1; touch /var/nope'
     test ! -e "$root/read-only"
     test ! -e "$root/var/nope"
     # volatile=overlay: tmpfs overlay is mounted over rootfs
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --volatile=overlay \
                    bash -xec 'test -e /usr/has-usr; touch /nope; touch /var/also-nope; touch /usr/nope-too'
     test ! -e "$root/nope"
@@ -138,27 +143,31 @@ testcase_sanity() {
     # --volatile= with -U
     touch "$root/usr/has-usr"
     # volatile(=yes): rootfs is tmpfs, /usr/ from the OS tree is mounted read only
-    systemd-nspawn --directory="$root"\
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --volatile \
                    -U \
                    bash -xec 'test -e /usr/has-usr; touch /usr/read-only && exit 1; touch /nope'
     test ! -e "$root/nope"
     test ! -e "$root/usr/read-only"
-    systemd-nspawn --directory="$root"\
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --volatile=yes \
                    -U \
                    bash -xec 'test -e /usr/has-usr; touch /usr/read-only && exit 1; touch /nope'
     test ! -e "$root/nope"
     test ! -e "$root/usr/read-only"
     # volatile=state: rootfs is read-only, /var/ is tmpfs
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --volatile=state \
                    -U \
                    bash -xec 'test -e /usr/has-usr; mountpoint /var; touch /read-only && exit 1; touch /var/nope'
     test ! -e "$root/read-only"
     test ! -e "$root/var/nope"
     # volatile=overlay: tmpfs overlay is mounted over rootfs
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --volatile=overlay \
                    -U \
                    bash -xec 'test -e /usr/has-usr; touch /nope; touch /var/also-nope; touch /usr/nope-too'
@@ -167,13 +176,16 @@ testcase_sanity() {
     test ! -e "$root/usr/nope-too"
 
     # --machine=, --hostname=
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --machine="foo-bar.baz" \
                    bash -xec '[[ $(hostname) == foo-bar.baz ]]'
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --hostname="hello.world.tld" \
                    bash -xec '[[ $(hostname) == hello.world.tld ]]'
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --machine="foo-bar.baz" \
                    --hostname="hello.world.tld" \
                    bash -xec '[[ $(hostname) == hello.world.tld ]]'
@@ -181,13 +193,14 @@ testcase_sanity() {
     # --uuid=
     rm -f "$root/etc/machine-id"
     uuid="deadbeef-dead-dead-beef-000000000000"
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --uuid="$uuid" \
                    bash -xec "[[ \$container_uuid == $uuid ]]"
 
     # --as-pid2
-    systemd-nspawn --directory="$root" bash -xec '[[ $$ -eq 1 ]]'
-    systemd-nspawn --directory="$root" --as-pid2 bash -xec '[[ $$ -eq 2 ]]'
+    systemd-nspawn --register=no --directory="$root" bash -xec '[[ $$ -eq 1 ]]'
+    systemd-nspawn --register=no --directory="$root" --as-pid2 bash -xec '[[ $$ -eq 2 ]]'
 
     # --user=
     # "Fake" getent passwd's bare minimum, so we don't have to pull it in
@@ -208,28 +221,32 @@ EOF
     # bash will end up loading libnss_systemd.so which breaks when libnss_systemd.so is built with sanitizers
     # as bash isn't invoked with the necessary environment variables for that.
     useradd --root="$root" --uid 1000 --user-group --create-home testuser
-    systemd-nspawn --directory="$root" bash -xec '[[ $USER == root ]]'
-    systemd-nspawn --directory="$root" --user=testuser bash -xec '[[ $USER == testuser ]]'
+    systemd-nspawn --register=no --directory="$root" bash -xec '[[ $USER == root ]]'
+    systemd-nspawn --register=no --directory="$root" --user=testuser bash -xec '[[ $USER == testuser ]]'
 
     # --settings= + .nspawn files
     mkdir -p /run/systemd/nspawn/
     uuid="deadbeef-dead-dead-beef-000000000000"
     echo -ne "[Exec]\nMachineID=deadbeef-dead-dead-beef-111111111111" >/run/systemd/nspawn/foo-bar.nspawn
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --machine=foo-bar \
                    --settings=yes \
                    bash -xec '[[ $container_uuid == deadbeef-dead-dead-beef-111111111111 ]]'
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --machine=foo-bar \
                    --uuid="$uuid" \
                    --settings=yes \
                    bash -xec "[[ \$container_uuid == $uuid ]]"
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --machine=foo-bar \
                    --uuid="$uuid" \
                    --settings=override \
                    bash -xec '[[ $container_uuid == deadbeef-dead-dead-beef-111111111111 ]]'
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --machine=foo-bar \
                    --uuid="$uuid" \
                    --settings=trusted \
@@ -240,7 +257,8 @@ EOF
     touch "$tmpdir/1/one" "$tmpdir/2/two" "$tmpdir/3/three"
     touch "$tmpdir/foo"
     # --bind=
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    ${COVERAGE_BUILD_DIR:+--bind="$COVERAGE_BUILD_DIR"} \
                    --bind="$tmpdir:/foo" \
                    --bind="$tmpdir:/also-foo:noidmap,norbind" \
@@ -248,7 +266,8 @@ EOF
     # --bind= recursive
     rm -f "$tmpdir/bar"
     mount --bind "$tmpdir/1" "$tmpdir/2"
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    ${COVERAGE_BUILD_DIR:+--bind="$COVERAGE_BUILD_DIR"} \
                    --bind="$tmpdir:/foo" \
                    --bind="$tmpdir:/also-foo:noidmap,norbind" \
@@ -256,46 +275,52 @@ EOF
     umount "$tmpdir/2"
     test -e "$tmpdir/bar"
     # --bind-ro=
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --bind-ro="$tmpdir:/foo" \
                    --bind-ro="$tmpdir:/bar:noidmap,norbind" \
                    bash -xec 'test -e /foo/foo; touch /foo/baz && exit 1; touch /bar && exit 1; true'
     # --inaccessible=
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --inaccessible=/var \
                    bash -xec 'touch /var/foo && exit 1; true'
     # --tmpfs=
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --tmpfs=/var:rw,nosuid,noexec \
                    bash -xec 'touch /var/nope'
     test ! -e "$root/var/nope"
     # --overlay=
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --overlay="$tmpdir/1:$tmpdir/2:$tmpdir/3:/var" \
                    bash -xec 'test -e /var/one; test -e /var/two; test -e /var/three; touch /var/foo'
     test -e "$tmpdir/3/foo"
     # --overlay-ro=
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --overlay-ro="$tmpdir/1:$tmpdir/2:$tmpdir/3:/var" \
                    bash -xec 'test -e /var/one; test -e /var/two; test -e /var/three; touch /var/nope && exit 1; true'
     test ! -e "$tmpdir/3/nope"
     rm -fr "$tmpdir"
 
     # --port (sanity only)
-    systemd-nspawn --network-veth --directory="$root" --port=80 --port=90 true
-    systemd-nspawn --network-veth --directory="$root" --port=80:8080 true
-    systemd-nspawn --network-veth --directory="$root" --port=tcp:80 true
-    systemd-nspawn --network-veth --directory="$root" --port=tcp:80:8080 true
-    systemd-nspawn --network-veth --directory="$root" --port=udp:80 true
-    systemd-nspawn --network-veth --directory="$root" --port=udp:80:8080 --port=tcp:80:8080 true
-    (! systemd-nspawn --network-veth --directory="$root" --port= true)
-    (! systemd-nspawn --network-veth --directory="$root" --port=-1 true)
-    (! systemd-nspawn --network-veth --directory="$root" --port=: true)
-    (! systemd-nspawn --network-veth --directory="$root" --port=icmp:80:8080 true)
-    (! systemd-nspawn --network-veth --directory="$root" --port=tcp::8080 true)
-    (! systemd-nspawn --network-veth --directory="$root" --port=8080: true)
+    systemd-nspawn --register=no --network-veth --directory="$root" --port=80 --port=90 true
+    systemd-nspawn --register=no --network-veth --directory="$root" --port=80:8080 true
+    systemd-nspawn --register=no --network-veth --directory="$root" --port=tcp:80 true
+    systemd-nspawn --register=no --network-veth --directory="$root" --port=tcp:80:8080 true
+    systemd-nspawn --register=no --network-veth --directory="$root" --port=udp:80 true
+    systemd-nspawn --register=no --network-veth --directory="$root" --port=udp:80:8080 --port=tcp:80:8080 true
+    (! systemd-nspawn --register=no --network-veth --directory="$root" --port= true)
+    (! systemd-nspawn --register=no --network-veth --directory="$root" --port=-1 true)
+    (! systemd-nspawn --register=no --network-veth --directory="$root" --port=: true)
+    (! systemd-nspawn --register=no --network-veth --directory="$root" --port=icmp:80:8080 true)
+    (! systemd-nspawn --register=no --network-veth --directory="$root" --port=tcp::8080 true)
+    (! systemd-nspawn --register=no --network-veth --directory="$root" --port=8080: true)
     # Exercise adding/removing ports from an interface
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --network-veth \
                    --port=6667 \
                    --port=80:8080 \
@@ -305,12 +330,14 @@ EOF
 
     # --load-credential=, --set-credential=
     echo "foo bar" >/tmp/cred.path
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --load-credential=cred.path:/tmp/cred.path \
                    --set-credential="cred.set:hello world" \
                    bash -xec '[[ "$(</run/host/credentials/cred.path)" == "foo bar" ]]; [[ "$(</run/host/credentials/cred.set)" == "hello world" ]]'
     # Combine with --user to ensure creds are still readable
-    systemd-nspawn --directory="$root" \
+    systemd-nspawn --register=no \
+                   --directory="$root" \
                    --user=testuser \
                    --no-new-privileges=yes \
                    --load-credential=cred.path:/tmp/cred.path \
@@ -319,9 +346,9 @@ EOF
     rm -f /tmp/cred.path
 
     # Assorted tests
-    systemd-nspawn --directory="$root" --suppress-sync=yes bash -xec 'echo hello'
+    systemd-nspawn --register=no --directory="$root" --suppress-sync=yes bash -xec 'echo hello'
     systemd-nspawn --capability=help
-    systemd-nspawn --directory="$root" --capability=all bash -xec 'echo hello'
+    systemd-nspawn --register=no --directory="$root" --capability=all bash -xec 'echo hello'
     systemd-nspawn --resolv-conf=help
     systemd-nspawn --timezone=help
 
@@ -1311,7 +1338,7 @@ testcase_fuse() {
     #    "cat: -: Operation not permitted"                   # pass the test; opened but not read
     #    "bash: line 1: /dev/fuse: Operation not permitted"  # fail the test; could not open
     #    ""                                                  # fail the test; reading worked
-    [[ "$(systemd-nspawn --pipe --directory="$root" \
+    [[ "$(systemd-nspawn --register=no --pipe --directory="$root" \
               bash -c 'cat <>/dev/fuse' 2>&1)" == 'cat: -: Operation not permitted' ]]
 
     rm -fr "$root"
@@ -1351,7 +1378,7 @@ testcase_unpriv_fuse() {
 }
 
 test_tun() {
-    systemd-nspawn "$@" bash -xec '[[ -c /dev/net/tun ]]; [[ "$(stat /dev/net/tun --format=%u)" == 0 ]]; [[ "$(stat /dev/net/tun --format=%g)" == 0 ]]'
+    systemd-nspawn --register=no "$@" bash -xec '[[ -c /dev/net/tun ]]; [[ "$(stat /dev/net/tun --format=%u)" == 0 ]]; [[ "$(stat /dev/net/tun --format=%g)" == 0 ]]'
 
     # check if the owner of the host device is unchanged, see issue #34243.
     [[ "$(stat /dev/net/tun --format=%u)" == 0 ]]
@@ -1360,7 +1387,7 @@ test_tun() {
     # Without DeviceAllow= for /dev/net/tun, see issue #35116.
     systemd-run \
         --wait -p Environment=SYSTEMD_LOG_LEVEL=debug -p DevicePolicy=closed -p DeviceAllow="char-pts rw" \
-        systemd-nspawn "$@" bash -xec '[[ ! -e /dev/net/tun ]]'
+        systemd-nspawn --register=no "$@" bash -xec '[[ ! -e /dev/net/tun ]]'
 
     [[ "$(stat /dev/net/tun --format=%u)" == 0 ]]
     [[ "$(stat /dev/net/tun --format=%g)" == 0 ]]
@@ -1440,7 +1467,7 @@ testcase_link_journal_host() {
 
     for i in no yes pick; do
         systemd-nspawn \
-            --directory="$root" --private-users="$i" --link-journal=host \
+            --register=no --directory="$root" --private-users="$i" --link-journal=host \
             bash -xec 'p="/var/log/journal/$(cat /etc/machine-id)"; mountpoint "$p"; [[ "$(stat "$p" --format=%u)" == 0 ]]; touch "$p/hoge"'
 
         [[ "$(stat "${hoge}/hoge" --format=%u)" == 0 ]]