diff --git a/include/neighbor.h b/include/neighbor.h
index 63d4dc8b56..52e90e6e6a 100644
--- a/include/neighbor.h
+++ b/include/neighbor.h
@@ -241,6 +241,7 @@ class NeighborVector : public NeighborVectorBase
         }
         return lo;
 #endif
+#if defined(USE_AVX512) || defined(USE_AVX2)
         // Scalar tail for SIMD paths (remaining < 8 elements)
         for (; lo < size; lo++)
         {
@@ -250,6 +251,7 @@ class NeighborVector : public NeighborVectorBase
                 return lo;
         }
         return lo;
+#endif
     }
 
     std::vector<Neighbor> _data;