tracker/udp/client.go | 4 +++-

diff --git a/tracker/udp/client.go b/tracker/udp/client.go
index c7f9392d36a7bab7df6d09719e2bc1a35ba54e88..0095a912aaac378995dd359f4bfa57d6d53e5380 100644
--- a/tracker/udp/client.go
+++ b/tracker/udp/client.go
@@ -164,7 +164,9 @@ 		if dr.Header.Action == action {
 			respBody = dr.Body
 			addr = dr.Addr
 		} else if dr.Header.Action == ActionError {
-			err = fmt.Errorf("error response: %s", dr.Body)
+			// I've seen "Connection ID mismatch.^@" in less and other tools, I think they're just
+			// not handling a trailing \x00 nicely.
+			err = fmt.Errorf("error response: %#q", dr.Body)
 		} else {
 			err = fmt.Errorf("unexpected response action %v", dr.Header.Action)
 		}