diff --git a/RNS/Transport.py b/RNS/Transport.py
index 07559b6..5429cab 100755
--- a/RNS/Transport.py
+++ b/RNS/Transport.py
@@ -893,7 +893,8 @@ class Transport:
                             receipt_validated = receipt.validate_proof_packet(packet)
 
                         if receipt_validated:
-                            Transport.receipts.remove(receipt)
+                            if receipt in Transport.receipts:
+                                Transport.receipts.remove(receipt)
 
         Transport.jobs_locked = False