diff --git a/man/systemd.service.xml b/man/systemd.service.xml
index 9a0b72aca9..48c1ea15b1 100644
--- a/man/systemd.service.xml
+++ b/man/systemd.service.xml
@@ -782,15 +782,14 @@
 
       <varlistentry>
         <term><varname>NonBlocking=</varname></term>
-        <listitem><para>Set the <constant>O_NONBLOCK</constant> flag
-        for all file descriptors passed via socket-based activation.
-        If true, all file descriptors >= 3 (i.e. all except stdin,
-        stdout, and stderr) will have the
-        <constant>O_NONBLOCK</constant> flag set and hence are in
-        non-blocking mode. This option is only useful in conjunction
-        with a socket unit, as described in
-        <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
-        Defaults to false.</para></listitem>
+        <listitem><para>Set the <constant>O_NONBLOCK</constant> flag for all file descriptors passed via socket-based
+        activation. If true, all file descriptors >= 3 (i.e. all except stdin, stdout, stderr), excluding those passed
+        in via the file descriptor storage logic (see <varname>FileDescriptorStoreMax=</varname> for details), will
+        have the <constant>O_NONBLOCK</constant> flag set and hence are in non-blocking mode. This option is only
+        useful in conjunction with a socket unit, as described in
+        <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> and has no
+        effect on file descriptors which were previously saved in the file-descriptor store for example.  Defaults to
+        false.</para></listitem>
       </varlistentry>
 
       <varlistentry>
diff --git a/src/core/execute.c b/src/core/execute.c
index e97651105e..7d9fc037b9 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -157,7 +157,7 @@ static int shift_fds(int fds[], unsigned n_fds) {
         return 0;
 }
 
-static int flags_fds(const int fds[], unsigned n_fds, bool nonblock) {
+static int flags_fds(const int fds[], unsigned n_fds, unsigned n_socket_fds, bool nonblock) {
         unsigned i;
         int r;
 
@@ -166,13 +166,16 @@ static int flags_fds(const int fds[], unsigned n_fds, bool nonblock) {
 
         assert(fds);
 
-        /* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags */
+        /* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags.
+         * O_NONBLOCK only applies to socket activation though. */
 
         for (i = 0; i < n_fds; i++) {
 
-                r = fd_nonblock(fds[i], nonblock);
-                if (r < 0)
-                        return r;
+                if (i < n_socket_fds) {
+                        r = fd_nonblock(fds[i], nonblock);
+                        if (r < 0)
+                                return r;
+                }
 
                 /* We unconditionally drop FD_CLOEXEC from the fds,
                  * since after all we want to pass these fds to our
@@ -2242,6 +2245,7 @@ static int exec_child(
                 int socket_fd,
                 int named_iofds[3],
                 int *fds, unsigned n_fds,
+                unsigned n_socket_fds,
                 char **files_env,
                 int user_lookup_fd,
                 int *exit_status,
@@ -2669,7 +2673,7 @@ static int exec_child(
         if (r >= 0)
                 r = shift_fds(fds, n_fds);
         if (r >= 0)
-                r = flags_fds(fds, n_fds, context->non_blocking);
+                r = flags_fds(fds, n_fds, n_socket_fds, context->non_blocking);
         if (r < 0) {
                 *exit_status = EXIT_FDS;
                 return r;
@@ -2909,7 +2913,8 @@ int exec_spawn(Unit *unit,
                pid_t *ret) {
 
         _cleanup_strv_free_ char **files_env = NULL;
-        int *fds = NULL; unsigned n_fds = 0;
+        int *fds = NULL;
+        unsigned n_fds = 0, n_socket_fds = 0;
         _cleanup_free_ char *line = NULL;
         int socket_fd, r;
         int named_iofds[3] = { -1, -1, -1 };
@@ -2942,6 +2947,7 @@ int exec_spawn(Unit *unit,
                 socket_fd = -1;
                 fds = params->fds;
                 n_fds = params->n_fds;
+                n_socket_fds = params->n_socket_fds;
         }
 
         r = exec_context_named_iofds(unit, context, params, named_iofds);
@@ -2980,6 +2986,7 @@ int exec_spawn(Unit *unit,
                                socket_fd,
                                named_iofds,
                                fds, n_fds,
+                               n_socket_fds,
                                files_env,
                                unit->manager->user_lookup_fds[1],
                                &exit_status,
diff --git a/src/core/execute.h b/src/core/execute.h
index 9f2b6fd39e..dee7af1423 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -247,6 +247,7 @@ struct ExecParameters {
         int *fds;
         char **fd_names;
         unsigned n_fds;
+        unsigned n_socket_fds;
 
         ExecFlags flags;
         bool selinux_context_net:1;
diff --git a/src/core/service.c b/src/core/service.c
index b45929e535..370a6316e7 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -1068,14 +1068,16 @@ static int service_coldplug(Unit *u) {
         return 0;
 }
 
-static int service_collect_fds(Service *s, int **fds, char ***fd_names) {
+static int service_collect_fds(Service *s, int **fds, char ***fd_names, unsigned *n_socket_fds) {
         _cleanup_strv_free_ char **rfd_names = NULL;
         _cleanup_free_ int *rfds = NULL;
-        int rn_fds = 0, r;
+        unsigned rn_socket_fds = 0;
+        int rn_fds = 0,  r;
 
         assert(s);
         assert(fds);
         assert(fd_names);
+        assert(n_socket_fds);
 
         if (s->socket_fd >= 0) {
 
@@ -1138,6 +1140,8 @@ static int service_collect_fds(Service *s, int **fds, char ***fd_names) {
                 }
         }
 
+        rn_socket_fds = rn_fds;
+
         if (s->n_fd_store > 0) {
                 ServiceFDStore *fs;
                 char **nl;
@@ -1169,6 +1173,7 @@ static int service_collect_fds(Service *s, int **fds, char ***fd_names) {
 
         *fds = rfds;
         *fd_names = rfd_names;
+        *n_socket_fds = rn_socket_fds;
 
         rfds = NULL;
         rfd_names = NULL;
@@ -1204,7 +1209,7 @@ static int service_spawn(
 
         _cleanup_strv_free_ char **final_env = NULL, **our_env = NULL, **fd_names = NULL;
         _cleanup_free_ int *fds = NULL;
-        unsigned n_fds = 0, n_env = 0;
+        unsigned n_fds = 0, n_socket_fds = 0, n_env = 0;
         const char *path;
         pid_t pid;
 
@@ -1248,7 +1253,7 @@ static int service_spawn(
             s->exec_context.std_output == EXEC_OUTPUT_SOCKET ||
             s->exec_context.std_error == EXEC_OUTPUT_SOCKET) {
 
-                r = service_collect_fds(s, &fds, &fd_names);
+                r = service_collect_fds(s, &fds, &fd_names, &n_socket_fds);
                 if (r < 0)
                         return r;
 
@@ -1348,6 +1353,7 @@ static int service_spawn(
         exec_params.fds = fds;
         exec_params.fd_names = fd_names;
         exec_params.n_fds = n_fds;
+        exec_params.n_socket_fds = n_socket_fds;
         exec_params.confirm_spawn = manager_get_confirm_spawn(UNIT(s)->manager);
         exec_params.cgroup_supported = UNIT(s)->manager->cgroup_supported;
         exec_params.cgroup_path = path;