diff --git a/packages/SwingSet/test/upgrade/test-upgrade-replay.js b/packages/SwingSet/test/upgrade/test-upgrade-replay.js
index 7e26181248d6..48047c702900 100644
--- a/packages/SwingSet/test/upgrade/test-upgrade-replay.js
+++ b/packages/SwingSet/test/upgrade/test-upgrade-replay.js
@@ -36,6 +36,7 @@ test.before(async t => {
 test('replay after upgrade', async t => {
   const config = {
     bootstrap: 'bootstrap',
+    defaultManagerType: 'xsnap',
     vats: {
       bootstrap: { sourceSpec: bfile('bootstrap-upgrade-replay.js') },
     },
diff --git a/packages/SwingSet/test/vat-admin/test-replay.js b/packages/SwingSet/test/vat-admin/test-replay.js
index c8c9cf7f3c04..f380bd0a1669 100644
--- a/packages/SwingSet/test/vat-admin/test-replay.js
+++ b/packages/SwingSet/test/vat-admin/test-replay.js
@@ -28,6 +28,7 @@ test.serial('replay dynamic vat', async t => {
       },
     },
     bootstrap: 'bootstrap',
+    defaultReapInterval: 'never',
   };
 
   const ss1 = initSwingStore();