diff --git a/protocol.c b/protocol.c
index 9dde122..da5d618 100644
--- a/protocol.c
+++ b/protocol.c
@@ -1411,8 +1411,8 @@ enet_protocol_check_outgoing_commands (ENetHost * host, ENetPeer * peer)
                   outgoingCommand -> sendAttempts < 1 && 
                   ! (outgoingCommand -> reliableSequenceNumber % ENET_PEER_RELIABLE_WINDOW_SIZE) &&
                   (channel -> reliableWindows [(reliableWindow + ENET_PEER_RELIABLE_WINDOWS - 1) % ENET_PEER_RELIABLE_WINDOWS] >= ENET_PEER_RELIABLE_WINDOW_SIZE ||
-                    channel -> usedReliableWindows & ((((1 << ENET_PEER_FREE_RELIABLE_WINDOWS) - 1) << reliableWindow) | 
-                      (((1 << ENET_PEER_FREE_RELIABLE_WINDOWS) - 1) >> (ENET_PEER_RELIABLE_WINDOWS - reliableWindow)))))
+                    channel -> usedReliableWindows & ((((1 << (ENET_PEER_FREE_RELIABLE_WINDOWS + 1)) - 1) << reliableWindow) |
+                      (((1 << (ENET_PEER_FREE_RELIABLE_WINDOWS + 1)) - 1) >> (ENET_PEER_RELIABLE_WINDOWS - reliableWindow)))))
                 windowWrap = 1;
              if (windowWrap)
              {