diff --git a/Atomic/Mailbox.h b/Atomic/Mailbox.h
index 936ab81..1251434 100644
--- a/Atomic/Mailbox.h
+++ b/Atomic/Mailbox.h
@@ -15,6 +15,7 @@ static_assert( __cplusplus > 2020'99 );
 #include <Alepha/Thread.h>
 #include <Alepha/Exception.h>
 #include <Alepha/assertion.h>
+#include <Alepha/error.h>
 
 namespace Alepha::Hydrogen::Atomic  ::detail::  Mailbox_m
 {
@@ -158,14 +159,14 @@ namespace Alepha::Hydrogen::Atomic  ::detail::  Mailbox_m
 						if( pos == end( filled ) ) raiseFinished();
 						mustFinish= true;
 					}
-					assert( &*pos != nullptr );
-					assert( pos != end( filled ) );
+					assertion( &*pos != nullptr );
+					assertion( pos != end( filled ) );
 				}
 				else error() << "We did not hit the sync point." << std::endl;
-				assert( pos != end( filled ) );
-				assert( not filled.empty() );
+				assertion( pos != end( filled ) );
+				assertion( not filled.empty() );
 
-				assert( &*pos != nullptr );
+				assertion( &*pos != nullptr );
 				return std::move( *pos++ );
 			}
 
diff --git a/Atomic/Mailbox.test/0.cc b/Atomic/Mailbox.test/0.cc
index ae03dbe..c420352 100644
--- a/Atomic/Mailbox.test/0.cc
+++ b/Atomic/Mailbox.test/0.cc
@@ -5,6 +5,8 @@ static_assert( __cplusplus > 2020'99 );
 #include <Alepha/Testing/test.h>
 #include <Alepha/Testing/TableTest.h>
 
+#include <cassert>
+
 static auto init= Alepha::Utility::enroll <=[]
 {
 	using namespace Alepha::Testing::exports;