diff --git a/src/main/di.ts b/src/main/di.ts
index 45907aee8b..bff54b3ea2 100644
--- a/src/main/di.ts
+++ b/src/main/di.ts
@@ -80,6 +80,14 @@ if (!fs.existsSync(configDataFolderPath)) {
     fs.mkdirSync(configDataFolderPath);
 }
 
+const WATCHDOG_FILENAME = "watchdog.json";
+export const watchdogFilePath = path.join(
+    configDataFolderPath,
+    WATCHDOG_FILENAME,
+);
+
+
+
 const STATE_FILENAME = "state.json";
 export const stateFilePath = path.join(
     configDataFolderPath,
diff --git a/src/main/redux/sagas/index.ts b/src/main/redux/sagas/index.ts
index 1316338f1d..741ddb33c0 100644
--- a/src/main/redux/sagas/index.ts
+++ b/src/main/redux/sagas/index.ts
@@ -42,6 +42,8 @@ import { sagaCustomizationProfileProvisioning } from "./customization";
 import isURL from "validator/lib/isURL";
 import { publicationIntegrityChecker } from "./publication/checker";
 import { error } from "readium-desktop/main/tools/error";
+import { watchdog } from "./watchdog";
+import { diMainGet } from "readium-desktop/main/di";
 
 // Logger
 const filename_ = "readium-desktop:main:saga:app";
@@ -64,6 +66,11 @@ export function* rootSaga() {
             call(appSaga.init),
             call(keyboardShortcuts.init),
             call(sagaCustomizationProfileProvisioning),
+            call(function*() {
+
+                const state = diMainGet("store").getState();
+                debug("__TIME__", (state as any).__t, new Date((state as any).__t));
+            }),
         ]);
 
     } catch (e) {
@@ -89,6 +96,14 @@ export function* rootSaga() {
         }
     });
 
+    yield* spawnTyped(function* () {
+        try {
+            yield* callTyped(watchdog);
+        } catch (e) {
+            error(filename_, e);
+        }
+    });
+
     // customization profile acquire, provisioned and activate
     yield customization.saga();
 
diff --git a/src/main/redux/sagas/persist.ts b/src/main/redux/sagas/persist.ts
index 3f1a85b3de..8180423166 100644
--- a/src/main/redux/sagas/persist.ts
+++ b/src/main/redux/sagas/persist.ts
@@ -23,6 +23,7 @@ import { takeSpawnEvery } from "readium-desktop/common/redux/sagas/takeSpawnEver
 import { ReaderConfig } from "readium-desktop/common/models/reader";
 import { IDictWinRegistryReaderState } from "../states/win/registry/reader";
 import { _APP_VERSION } from "readium-desktop/preprocessor-directives";
+import { resetWatchdog } from "./watchdog";
 
 const DEBOUNCE_TIME = 3 * 60 * 1000; // 3 min
 const PUBLICATION_STORAGE_DEBOUNCE_TIME = 10 * 1000; // 10 secs
@@ -102,6 +103,8 @@ export function* needToPersistFinalState() {
     const nextState = yield* selectTyped((store: RootState) => store);
     yield call(() => persistStateToFs(nextState));
     yield call(() => needToPersistPatch());
+
+    yield call(() => resetWatchdog());
 }
 
 export function* needToPersistPatch() {
diff --git a/src/main/redux/sagas/watchdog.ts b/src/main/redux/sagas/watchdog.ts
new file mode 100644
index 0000000000..d678c42906
--- /dev/null
+++ b/src/main/redux/sagas/watchdog.ts
@@ -0,0 +1,51 @@
+// ==LICENSE-BEGIN==
+// Copyright 2017 European Digital Reading Lab. All rights reserved.
+// Licensed to the Readium Foundation under one or more contributor license agreements.
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file exposed on Github (readium) in the project repository.
+// ==LICENSE-END==
+
+import * as fs from "node:fs";
+import debug_ from "debug";
+import { call as callTyped, delay as delayTyped, SagaGenerator } from "typed-redux-saga";
+import { watchdogFilePath } from "readium-desktop/main/di";
+import { ok } from "readium-desktop/common/utils/assert";
+
+// Logger
+const filename_ = "readium-desktop:main:redux:sagas:watchdog";
+const debug = debug_(filename_);
+debug("_");
+
+export const watchdog = function* (): SagaGenerator<void> {
+
+    let counter = 0;
+
+    while (1) {
+        counter++;
+        if (counter >= Number.MAX_SAFE_INTEGER) {
+            counter = 0;
+        }
+        const time = (new Date()).toISOString();
+        const jsonObj = {time, counter};
+        const data = JSON.stringify(jsonObj); 
+        // debug("WATCHDOG", jsonObj);
+
+        yield* delayTyped(1000); // 1s
+        yield* callTyped(async () => await fs.promises.writeFile(watchdogFilePath, data, { encoding: "utf-8" }));
+        const dataRead = yield* callTyped(async () => await fs.promises.readFile(watchdogFilePath, { encoding: "utf8" }));
+        ok(dataRead === data, "Watchdog error !?");
+    }
+};
+
+export const resetWatchdog = () => {
+
+    fs.rmSync(watchdogFilePath);
+};
+
+export const readWatchdog = async () => {
+
+    const dataRead = await fs.promises.readFile(watchdogFilePath, { encoding: "utf8" });
+    const jsonObj = JSON.parse(dataRead);
+    const time = new Date(jsonObj.time);
+    return time;
+};
diff --git a/src/main/redux/store/memory.ts b/src/main/redux/store/memory.ts
index 26d778eb6b..82c48c12ea 100644
--- a/src/main/redux/store/memory.ts
+++ b/src/main/redux/store/memory.ts
@@ -33,6 +33,8 @@ import { IReaderStateReaderSession } from "readium-desktop/common/redux/states/r
 import { IWinRegistryReaderState } from "readium-desktop/main/redux/states/win/registry/reader";
 import { ReaderConfig } from "readium-desktop/common/models/reader";
 import { IRTLFlipState } from "readium-desktop/common/redux/states/renderer/rtlFlip";
+import { readWatchdog } from "../sagas/watchdog";
+import { dialog } from "electron";
 
 // import { composeWithDevTools } from "remote-redux-devtools";
 const REDUX_REMOTE_DEVTOOLS_PORT = 7770;
@@ -113,8 +115,35 @@ export async function initStore()
 
         const jsonStr = await fs.promises.readFile(stateFilePath, { encoding: "utf8" });
         const json = JSON.parse(jsonStr);
-        if (test(json))
+        if (test(json)) {
             reduxState = json;
+        }
+
+        try {
+            const timestr = (reduxState as any).__t;
+            const version = (reduxState as any).__v;
+            debug(`Last state.json saved time: ${timestr} from v=${version}`);
+            delete (reduxState as any).__t;
+            delete (reduxState as any).__v;
+
+            const wdTime = await readWatchdog();
+            debug(`Watchdog time: ${wdTime.toUTCString()}`);
+
+            if (wdTime) {
+                debug("A crash occurred. The watchdog file must be removed when Thorium closes.");
+                const p = dialog.showMessageBox(undefined, { message: "A crash occurred", type: "error", buttons: ["OK"] });
+
+                p.then((response) => {
+                    debug("RES:", response);
+                }).catch((e) => {
+                    debug("dialog.showMessageBox CRASHED", e);
+
+                });
+            }
+            
+        } catch {
+            // ignore
+        }
 
         debug("STATE LOADED FROM FS");
         debug("😍😍😍😍😍😍😍😍");