diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 24c2b2fad..7088c20cb 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -17,6 +17,7 @@ from ._base import BaseHandler
 
 from synapse.streams.config import PaginationConfig
 from synapse.api.constants import Membership, EventTypes
+from synapse.util import unwrapFirstError
 
 from twisted.internet import defer
 
@@ -209,9 +210,10 @@ class SyncHandler(BaseHandler):
         joined = []
         invited = []
         archived = []
+        deferreds = []
         for event in room_list:
             if event.membership == Membership.JOIN:
-                room_sync = yield self.full_state_sync_for_joined_room(
+                room_sync_deferred = self.full_state_sync_for_joined_room(
                     room_id=event.room_id,
                     sync_config=sync_config,
                     now_token=now_token,
@@ -220,7 +222,8 @@ class SyncHandler(BaseHandler):
                     tags_by_room=tags_by_room,
                     account_data_by_room=account_data_by_room,
                 )
-                joined.append(room_sync)
+                room_sync_deferred.addCallback(joined.append)
+                deferreds.append(room_sync_deferred)
             elif event.membership == Membership.INVITE:
                 invite = yield self.store.get_event(event.event_id)
                 invited.append(InvitedSyncResult(
@@ -231,7 +234,7 @@ class SyncHandler(BaseHandler):
                 leave_token = now_token.copy_and_replace(
                     "room_key", "s%d" % (event.stream_ordering,)
                 )
-                room_sync = yield self.full_state_sync_for_archived_room(
+                room_sync_deferred = self.full_state_sync_for_archived_room(
                     sync_config=sync_config,
                     room_id=event.room_id,
                     leave_event_id=event.event_id,
@@ -240,7 +243,12 @@ class SyncHandler(BaseHandler):
                     tags_by_room=tags_by_room,
                     account_data_by_room=account_data_by_room,
                 )
-                archived.append(room_sync)
+                room_sync_deferred.addCallback(archived.append)
+                deferreds.append(room_sync_deferred)
+
+        yield defer.gatherResults(
+            deferreds, consumeErrors=True
+        ).addErrback(unwrapFirstError)
 
         defer.returnValue(SyncResult(
             presence=presence,
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index f0a637a6d..3f8ce701d 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -354,17 +354,20 @@ class SyncRestServlet(RestServlet):
             logger.debug("Replacing %s with %s in state dict",
                          timeline_event.event_id, prev_event_id)
 
-            if prev_event_id is None:
+            prev_content = timeline_event.unsigned.get('prev_content')
+            prev_sender = timeline_event.unsigned.get('prev_sender')
+            if prev_event_id is None or not prev_content or not prev_sender:
                 del result[event_key]
             else:
                 result[event_key] = FrozenEvent({
                     "type": timeline_event.type,
                     "state_key": timeline_event.state_key,
-                    "content": timeline_event.unsigned['prev_content'],
-                    "sender": timeline_event.unsigned['prev_sender'],
+                    "content": prev_content,
+                    "sender": prev_sender,
                     "event_id": prev_event_id,
                     "room_id": timeline_event.room_id,
                 })
+
             logger.debug("New value: %r", result.get(event_key))
 
         return result
diff --git a/synapse/storage/search.py b/synapse/storage/search.py
index 00f89ff02..57c9cc1c5 100644
--- a/synapse/storage/search.py
+++ b/synapse/storage/search.py
@@ -85,6 +85,11 @@ class SearchStore(BackgroundUpdateStore):
                     # skip over it.
                     continue
 
+                if not isinstance(value, basestring):
+                    # If the event body, name or topic isn't a string
+                    # then skip over it
+                    continue
+
                 event_search_rows.append((event_id, room_id, key, value))
 
             if isinstance(self.database_engine, PostgresEngine):