diff --git a/test/libcxx/thread/futures/futures.promise/set_exception.pass.cpp b/test/libcxx/thread/futures/futures.promise/set_exception.pass.cpp
index abfbb685d..805aee138 100644
--- a/test/libcxx/thread/futures/futures.promise/set_exception.pass.cpp
+++ b/test/libcxx/thread/futures/futures.promise/set_exception.pass.cpp
@@ -14,6 +14,9 @@
 // MODULES_DEFINES: _LIBCPP_DEBUG_USE_EXCEPTIONS
 // MODULES_DEFINES: _LIBCPP_DEBUG=0
 
+// Can't test the system lib because this test enables debug mode
+// UNSUPPORTED: with_system_cxx_lib
+
 // <future>
 
 // class promise<R>
diff --git a/test/libcxx/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp b/test/libcxx/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp
index 6736bae97..88061bb5f 100644
--- a/test/libcxx/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp
+++ b/test/libcxx/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp
@@ -14,6 +14,9 @@
 // MODULES_DEFINES: _LIBCPP_DEBUG_USE_EXCEPTIONS
 // MODULES_DEFINES: _LIBCPP_DEBUG=0
 
+// Can't test the system lib because this test enables debug mode
+// UNSUPPORTED: with_system_cxx_lib
+
 // <future>
 
 // class promise<R>