diff --git a/homeassistant/components/plex/sensor.py b/homeassistant/components/plex/sensor.py
index b1e93aec8c00da..65d1ba0371bd95 100644
--- a/homeassistant/components/plex/sensor.py
+++ b/homeassistant/components/plex/sensor.py
@@ -2,14 +2,16 @@
 import logging
 
 from homeassistant.core import callback
-from homeassistant.helpers.dispatcher import async_dispatcher_connect
+from homeassistant.helpers.dispatcher import async_dispatcher_connect, dispatcher_send
 from homeassistant.helpers.entity import Entity
+from homeassistant.helpers.event import async_call_later
 
 from .const import (
     CONF_SERVER_IDENTIFIER,
     DISPATCHERS,
     DOMAIN as PLEX_DOMAIN,
     NAME_FORMAT,
+    PLEX_UPDATE_PLATFORMS_SIGNAL,
     PLEX_UPDATE_SENSOR_SIGNAL,
     SERVERS,
 )
@@ -55,55 +57,30 @@ async def async_added_to_hass(self):
         )
         self.hass.data[PLEX_DOMAIN][DISPATCHERS][server_id].append(unsub)
 
-    @callback
-    def async_refresh_sensor(self, sessions):
+    async def async_refresh_sensor(self, sessions):
         """Set instance object and trigger an entity state update."""
-        self.sessions = sessions
-        self.async_schedule_update_ha_state(True)
-
-    @property
-    def name(self):
-        """Return the name of the sensor."""
-        return self._name
-
-    @property
-    def unique_id(self):
-        """Return the id of this plex client."""
-        return self._unique_id
-
-    @property
-    def should_poll(self):
-        """Return True if entity has to be polled for state."""
-        return False
-
-    @property
-    def state(self):
-        """Return the state of the sensor."""
-        return self._state
-
-    @property
-    def unit_of_measurement(self):
-        """Return the unit this state is expressed in."""
-        return "Watching"
+        _LOGGER.debug("Refreshing sensor [%s]", self.unique_id)
 
-    @property
-    def icon(self):
-        """Return the icon of the sensor."""
-        return "mdi:plex"
+        self.sessions = sessions
 
-    @property
-    def device_state_attributes(self):
-        """Return the state attributes."""
-        return {content[0]: content[1] for content in self._now_playing}
+        @callback
+        def update_plex(_):
+            dispatcher_send(
+                self.hass,
+                PLEX_UPDATE_PLATFORMS_SIGNAL.format(self._server.machine_identifier),
+            )
 
-    def update(self):
-        """Update method for Plex sensor."""
-        _LOGGER.debug("Refreshing sensor [%s]", self.unique_id)
         now_playing = []
         for sess in self.sessions:
             if sess.TYPE == "photo":
                 _LOGGER.debug("Photo session detected, skipping: %s", sess)
                 continue
+            if not sess.usernames:
+                _LOGGER.debug(
+                    "Session temporarily incomplete, will try again: %s", sess
+                )
+                async_call_later(self.hass, 5, update_plex)
+                return
             user = sess.usernames[0]
             device = sess.players[0].title
             now_playing_user = f"{user} - {device}"
@@ -113,8 +90,9 @@ def update(self):
                 # example:
                 # "Supernatural (2005) - s01e13 - Route 666"
                 season_title = sess.grandparentTitle
-                if sess.show().year is not None:
-                    season_title += f" ({sess.show().year!s})"
+                show = await self.hass.async_add_executor_job(sess.show)
+                if show.year is not None:
+                    season_title += f" ({show.year!s})"
                 season_episode = sess.seasonEpisode
                 episode_title = sess.title
                 now_playing_title = (
@@ -139,6 +117,43 @@ def update(self):
         self._state = len(self.sessions)
         self._now_playing = now_playing
 
+        self.async_write_ha_state()
+
+    @property
+    def name(self):
+        """Return the name of the sensor."""
+        return self._name
+
+    @property
+    def unique_id(self):
+        """Return the id of this plex client."""
+        return self._unique_id
+
+    @property
+    def should_poll(self):
+        """Return True if entity has to be polled for state."""
+        return False
+
+    @property
+    def state(self):
+        """Return the state of the sensor."""
+        return self._state
+
+    @property
+    def unit_of_measurement(self):
+        """Return the unit this state is expressed in."""
+        return "Watching"
+
+    @property
+    def icon(self):
+        """Return the icon of the sensor."""
+        return "mdi:plex"
+
+    @property
+    def device_state_attributes(self):
+        """Return the state attributes."""
+        return {content[0]: content[1] for content in self._now_playing}
+
     @property
     def device_info(self):
         """Return a device description for device registry."""