diff --git a/zerver/lib/import_realm.py b/zerver/lib/import_realm.py
index 57e4d774dc..4b1fdfcfca 100644
--- a/zerver/lib/import_realm.py
+++ b/zerver/lib/import_realm.py
@@ -903,6 +903,29 @@ def do_import_realm(import_dir: Path, subdomain: str) -> Realm:
     update_model_ids(Reaction, data, 'reaction')
     bulk_import_model(data, Reaction)
 
+    for user_profile in UserProfile.objects.filter(is_bot=False, realm=realm):
+        # Since we now unconditionally renumbers message IDs, we need
+        # to reset the user's pointer to what will be a valid value.
+        #
+        # For zulip->zulip imports, we could do something clever, but
+        # it should always be safe to reset to first unread message.
+        #
+        # Longer-term, the plan is to eliminate pointer as a concept.
+        first_unread_message = UserMessage.objects.filter(user_profile=user_profile).extra(
+            where=[UserMessage.where_unread()]
+        ).first()
+        if first_unread_message is not None:
+            user_profile.pointer = first_unread_message.message_id
+        else:
+            last_message = UserMessage.objects.filter(user_profile=user_profile).last()
+            if last_message is not None:
+                user_profile.pointer = last_message.message_id
+            else:
+                # -1 is the guard value for new user accounts with no messages.
+                user_profile.pointer = -1
+
+        user_profile.save(update_fields=["pointer"])
+
     # Do attachments AFTER message data is loaded.
     # TODO: de-dup how we read these json files.
     fn = os.path.join(import_dir, "attachment.json")