From cfd6d3ce0499d5dd5c740b20b5089b8f1e6ef09c Mon Sep 17 00:00:00 2001
From: Lonami Exo <totufals@hotmail.com>
Date: Wed, 8 May 2019 18:15:57 +0200
Subject: [PATCH] Fix catch-up when no pts is known

---
 telethon/client/updates.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/telethon/client/updates.py b/telethon/client/updates.py
index 7c3a359a..927fb411 100644
--- a/telethon/client/updates.py
+++ b/telethon/client/updates.py
@@ -154,6 +154,9 @@ class UpdateMethods(UserMethods):
         This can also be used to forcibly fetch new updates if there are any.
         """
         pts, date = self._state_cache[None]
+        if not pts:
+            return
+
         self.session.catching_up = True
         try:
             while True: