diff --git a/man/sd_id128_get_machine.xml b/man/sd_id128_get_machine.xml
index a778f8a2b0..8bc76b686b 100644
--- a/man/sd_id128_get_machine.xml
+++ b/man/sd_id128_get_machine.xml
@@ -144,6 +144,14 @@
           empty or all zeros.</para></listitem>
         </varlistentry>
 
+        <varlistentry>
+          <term><constant>-ENOPKG</constant></term>
+
+          <listitem><para>Returned by <function>sd_id128_get_machine()</function> and
+          <function>sd_id128_get_machine_app_specific()</function> when the content of
+          <filename>/etc/machine-id</filename> is <literal>uninitialized</literal>.</para></listitem>
+        </varlistentry>
+
         <varlistentry>
           <term><constant>-ENXIO</constant></term>