diff --git a/examples/cute/tutorial/blackwell/04_mma_tma_2sm_sm100.cu b/examples/cute/tutorial/blackwell/04_mma_tma_2sm_sm100.cu
index 2d4799f9fe..8e02a368a7 100644
--- a/examples/cute/tutorial/blackwell/04_mma_tma_2sm_sm100.cu
+++ b/examples/cute/tutorial/blackwell/04_mma_tma_2sm_sm100.cu
@@ -243,6 +243,9 @@ gemm_device(ATensor mA,                      // (Gemm_M, Gemm_K)
   using TmemAllocator = cute::TMEM::Allocator2Sm;
   TmemAllocator tmem_allocator{};
 
+  // Make sure all CTAs in Cluster are alive. 2SM mode TMEM alloc requires the leader and peer CTA have both
+  // been launched. We need this explicit cluster sync here to guarantee that.
+  cute::cluster_sync();
   if (elect_one_warp) {
     tmem_allocator.allocate(TmemAllocator::Sm100TmemCapacityColumns, &shared_storage.tmem_base_ptr);
   }
diff --git a/examples/cute/tutorial/blackwell/05_mma_tma_epi_sm100.cu b/examples/cute/tutorial/blackwell/05_mma_tma_epi_sm100.cu
index 8a058c5cf5..311012d56c 100644
--- a/examples/cute/tutorial/blackwell/05_mma_tma_epi_sm100.cu
+++ b/examples/cute/tutorial/blackwell/05_mma_tma_epi_sm100.cu
@@ -256,6 +256,9 @@ gemm_device(ATensor mA,                      // (Gemm_M, Gemm_K)
   using TmemAllocator = cute::TMEM::Allocator2Sm;
   TmemAllocator tmem_allocator{};
 
+  // Make sure all CTAs in Cluster are alive. 2SM mode TMEM alloc requires the leader and peer CTA have both
+  // been launched. We need this explicit cluster sync here to guarantee that.
+  cute::cluster_sync();
   if (elect_one_warp) {
     tmem_allocator.allocate(TmemAllocator::Sm100TmemCapacityColumns, &shared_storage.tmem_base_ptr);
   }