diff --git a/test/run-once/vitest.config.ts b/test/run-once/vitest.config.ts
index 8d93d710efcb..9ca84b2b94b0 100644
--- a/test/run-once/vitest.config.ts
+++ b/test/run-once/vitest.config.ts
@@ -2,6 +2,6 @@ import { defineConfig } from 'vite'
 
 export default defineConfig({
   test: {
-    poolOptions: { threads: { isolate: false } },
+    isolate: false,
   },
 })
diff --git a/test/stacktraces/fixtures/vite.config.ts b/test/stacktraces/fixtures/vite.config.ts
index 54b0069ddff0..64d31c38f6d1 100644
--- a/test/stacktraces/fixtures/vite.config.ts
+++ b/test/stacktraces/fixtures/vite.config.ts
@@ -41,12 +41,8 @@ export default defineConfig({
     },
   }],
   test: {
+    isolate: false,
     pool: 'forks',
-    poolOptions: {
-      forks: {
-        isolate: false,
-      },
-    },
     include: ['**/*.{test,spec}.{imba,?(c|m)[jt]s?(x)}'],
     setupFiles: ['./setup.js'],
   },