diff --git a/tig-challenges/src/vector_search.rs b/tig-challenges/src/vector_search.rs
index eb798b7..49c691f 100644
--- a/tig-challenges/src/vector_search.rs
+++ b/tig-challenges/src/vector_search.rs
@@ -118,6 +118,8 @@ impl Challenge {
                 .launch(cfg)?;
         }
 
+        stream.synchronize()?;
+
         let total_distance = stream.memcpy_dtov(&d_total_distance)?[0];
         let error_flag = stream.memcpy_dtov(&errorflag)?[0];