diff --git a/.eslintrc b/.eslintrc
index 7b35bc4..9667b89 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -33,6 +33,7 @@
     "function-paren-newline": "off",
     "id-length": "off",
     "indent": ["error", 2],
+    "init-declarations": "off",
     "jsx-quotes": ["error", "prefer-single"],
     "max-classes-per-file": "off",
     "max-lines": "off",
diff --git a/src/background/presenters/NotifyPresenter.ts b/src/background/presenters/NotifyPresenter.ts
index 8fa4acb..6498fbf 100644
--- a/src/background/presenters/NotifyPresenter.ts
+++ b/src/background/presenters/NotifyPresenter.ts
@@ -4,7 +4,20 @@ const NOTIFICATION_ID = 'vimvixen-update';
 
 @injectable()
 export default class NotifyPresenter {
-  async notify(
+  async notifyUpdated(version: string, onclick: () => void): Promise<void> {
+    let title = `Vim Vixen ${version} has been installed`;
+    let message = 'Click here to see release notes';
+    await this.notify(title, message, onclick);
+  }
+
+  async notifyInvalidSettings(onclick: () => void): Promise<void> {
+    let title = `Loaded settings is invalid`;
+    // eslint-disable-next-line max-len
+    let message = 'The default settings is used due to the last saved settings is invalid.  Check your current settings from the add-on preference';
+    await this.notify(title, message, onclick);
+  }
+
+  private async notify(
     title: string,
     message: string,
     onclick: () => void,
diff --git a/src/background/usecases/SettingUseCase.ts b/src/background/usecases/SettingUseCase.ts
index fd00f80..694d3c1 100644
--- a/src/background/usecases/SettingUseCase.ts
+++ b/src/background/usecases/SettingUseCase.ts
@@ -4,6 +4,7 @@ import PersistentSettingRepository
 import SettingRepository from '../repositories/SettingRepository';
 import { DefaultSettingData } from '../../shared/SettingData';
 import Settings from '../../shared/Settings';
+import NotifyPresenter from '../presenters/NotifyPresenter';
 
 @injectable()
 export default class SettingUseCase {
@@ -11,6 +12,7 @@ export default class SettingUseCase {
   constructor(
     private persistentSettingRepository: PersistentSettingRepository,
     private settingRepository: SettingRepository,
+    private notifyPresenter: NotifyPresenter,
   ) {
   }
 
@@ -24,8 +26,14 @@ export default class SettingUseCase {
       data = DefaultSettingData;
     }
 
-    let value = data.toSettings();
-    this.settingRepository.update(value);
+    let value: Settings;
+    try {
+      value = data.toSettings();
+    } catch (e) {
+      this.notifyPresenter.notifyInvalidSettings(() => {});
+      value = DefaultSettingData.toSettings();
+    }
+    this.settingRepository.update(value!!);
     return value;
   }
 }
diff --git a/src/background/usecases/VersionUseCase.ts b/src/background/usecases/VersionUseCase.ts
index 1d9ef8b..0ff0e9b 100644
--- a/src/background/usecases/VersionUseCase.ts
+++ b/src/background/usecases/VersionUseCase.ts
@@ -12,10 +12,8 @@ export default class VersionUseCase {
 
   notify(): Promise<void> {
     let manifest = browser.runtime.getManifest();
-    let title = `Vim Vixen ${manifest.version} has been installed`;
-    let message = 'Click here to see release notes';
     let url = this.releaseNoteUrl(manifest.version);
-    return this.notifyPresenter.notify(title, message, () => {
+    return this.notifyPresenter.notifyUpdated(manifest.version, () => {
       this.tabPresenter.create(url);
     });
   }