diff --git a/src/create_app.ts b/src/create_app.ts
index 3803d47c..4e0e4607 100644
--- a/src/create_app.ts
+++ b/src/create_app.ts
@@ -78,6 +78,7 @@ export default class CreateApp implements AppInterface {
   public isPrefetch: boolean
   public isPrerender: boolean
   public prefetchLevel?: number
+  public mountIdentifier?: symbol
   public fiber = false
   public routerMode: string
   public attrs?: Record<string, string>
@@ -287,6 +288,7 @@ export default class CreateApp implements AppInterface {
         this.routerMode = routerMode
 
         const dispatchBeforeMount = () => {
+          this.mountIdentifier = Symbol('mountIdentifier')
           dispatchLifecyclesEvent(
             this.container,
             this.name,
@@ -493,6 +495,8 @@ export default class CreateApp implements AppInterface {
     unmountcb?: CallableFunction,
     umdHookUnmountResult?: unknown,
   ): void {
+    this.mountIdentifier = undefined
+
     // dispatch state event to micro app
     dispatchCustomEventToMicroApp(this, 'statechange', {
       appState: appStates.UNMOUNT
diff --git a/src/source/scripts.ts b/src/source/scripts.ts
index 5fe38efd..3f53271b 100644
--- a/src/source/scripts.ts
+++ b/src/source/scripts.ts
@@ -320,11 +320,21 @@ export function fetchScriptsFromHtml (
 
   const fiberScriptTasks: fiberTasks = app.isPrefetch || app.fiber ? [] : null
 
+  const startIdentifier = app.mountIdentifier
+
   if (fetchScriptPromise.length) {
     promiseStream<string>(fetchScriptPromise, (res: {data: string, index: number}) => {
+      const address = fetchScriptPromiseInfo[res.index][0]
+      const scriptInfo = fetchScriptPromiseInfo[res.index][1]
+      const currIdentifier = app.mountIdentifier
+      if (startIdentifier !== currIdentifier) {
+        scriptInfo.code = res.data
+        // app has been unmounted, old sandbox is not valid anymore. should not execute script
+        throw new Error('app has been unmounted, abort loading script')
+      }
       injectFiberTask(fiberScriptTasks, () => fetchScriptSuccess(
-        fetchScriptPromiseInfo[res.index][0],
-        fetchScriptPromiseInfo[res.index][1],
+        address,
+        scriptInfo,
         res.data,
         app,
       ))
@@ -578,8 +588,14 @@ export function runDynamicRemoteScript (
   if (scriptInfo.code || isTypeModule(app, scriptInfo)) {
     defer(runDynamicScript)
   } else {
+    const startIdentifier = app.mountIdentifier
     fetchSource(address, app.name).then((code: string) => {
+      const currIdentifier = app.mountIdentifier
       scriptInfo.code = code
+      if (startIdentifier !== currIdentifier) {
+        // app has been unmounted, old sandbox is not valid anymore. should not execute script
+        throw new Error('app has been unmounted, abort loading script')
+      }
       runDynamicScript()
     }).catch((err) => {
       logError(err, app.name)
diff --git a/typings/global.d.ts b/typings/global.d.ts
index 18d4132f..6386b1f6 100644
--- a/typings/global.d.ts
+++ b/typings/global.d.ts
@@ -190,6 +190,7 @@ declare module '@micro-app/types' {
     isPrerender: boolean
     isReloading?: boolean
     prefetchLevel?: number
+    mountIdentifier?: symbol // used to identify if the app has been unmounted between async calls
     // defaultPage: string // default page when mount
     // baseroute: string // route prefix, default is ''
     // hiddenRouter: boolean // hide router info of child from browser url