diff --git a/websocket_managed_conn.go b/websocket_managed_conn.go
index 92536171f..5b2f895c9 100644
--- a/websocket_managed_conn.go
+++ b/websocket_managed_conn.go
@@ -475,7 +475,7 @@ func (rtm *RTM) handleEvent(typeStr string, event json.RawMessage) {
 	v, exists := EventMapping[typeStr]
 	if !exists {
 		rtm.Debugf("RTM Error - received unmapped event %q: %s\n", typeStr, string(event))
-		err := fmt.Errorf("RTM Error: Received unmapped event %q: %s", typeStr, string(event))
+		err := fmt.Errorf("RTM Error: Received unmapped event %q", typeStr)
 		rtm.IncomingEvents <- RTMEvent{"unmarshalling_error", &UnmarshallingErrorEvent{err}}
 		return
 	}
@@ -484,7 +484,7 @@ func (rtm *RTM) handleEvent(typeStr string, event json.RawMessage) {
 	err := json.Unmarshal(event, recvEvent)
 	if err != nil {
 		rtm.Debugf("RTM Error, could not unmarshall event %q: %s\n", typeStr, string(event))
-		err := fmt.Errorf("RTM Error: Could not unmarshall event %q: %s", typeStr, string(event))
+		err := fmt.Errorf("RTM Error: Could not unmarshall event %q", typeStr)
 		rtm.IncomingEvents <- RTMEvent{"unmarshalling_error", &UnmarshallingErrorEvent{err}}
 		return
 	}