diff --git a/tests/server/sockfilt.c b/tests/server/sockfilt.c
index 0e31dfcd4d..eb9d8e8697 100644
--- a/tests/server/sockfilt.c
+++ b/tests/server/sockfilt.c
@@ -921,7 +921,7 @@ static bool disc_handshake(void)
       }
       else if(!memcmp("DATA", buffer, 4)) {
         /* We must read more data to stay in sync */
-        logmsg("Throwing away %zd data bytes", buffer_len);
+        logmsg("Throwing away data bytes");
         if(!read_data_block(buffer, sizeof(buffer), &buffer_len))
           return FALSE;