Protecting personal data on the Xiaomi Redmi Note 9 smartphone is a task that many users put off “for later” until confidential information leaks. Meanwhile, you can set a password for individual applications (messengers, banking services, gallery) in literally 5 minutes using built-in MIUI tools or third-party solutions. In this article, we will analyze all the current ways: from the standard App Lock to creating a second workspace with a separate password.
The Redmi Note 9 (M2003J15SC/M2003J15SS) features two native application blocking methods at once, without the need to install additional software. However, each approach has nuances: for example, Second Space requires a phone restart, and App Lock can conflict with some versions of MIUI 12+. We tested all options on MIUI 12.5-14 firmware and identified key points that will help avoid errors.
Method 1: Built-in App Lock in MIUI
The easiest and fastest way to do this is to use the App Lock feature, which is integrated into the MIUI shell, which allows you to set a password (or fingerprint) for any application, including system applications. Importantly, for App Lock to work, you must pre-configure the screen lock (PIN, pattern lock or password).
To activate the protection:
- Open Settings → Applications → App Lock.
- When you first start, the system will ask you to create a password for App Lock (it may be different from the screen unlock password).
- In the list of applications, select the ones to block (for example, WhatsApp, SberBank Online, Gallery).
- Activate the switch next to the name of the application.
After setting up the locked application, a window will appear with a password request or fingerprint scanner every time you open the blocked application. Please note: if you are using MIUI 13+, App Lock has an additional Hide Notifications option in its settings – it allows you to hide the contents of notifications from blocked applications on the lock screen.
Set a password/pattern lock on the lock screen
Update MIUI to the latest version (at least 12.5)
Disable battery optimization for system applications
Synchronize the Mi Account data (in case of reset)
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⚠️ Note: If you forget your password from App Lock, you can only restore it through your Mi Account (linked to your phone.
Method 2: Second Space – a separate workspace
Second Space creates an isolated copy of the system with its own apps, settings, and password, which is useful if you want to separate your work apps from your personal apps completely, or if you give your kids a phone, unlike App Lock, it doesn't block a single application, but the entire profile with a unique password.
How to set up:
- Go to Settings → Special Options → Second Space.
- Click Create Second Space and follow the instructions (reboot your phone will be required).
- After the reboot, select Second Space on the lock screen and set it up as a new phone: set a password, add apps.
- To switch between spaces, swipe down the lock screen and select the desired profile.
The advantage of this method is that applications in Second Space are completely isolated: you can't open them without a second-space password, even if the main screen is unlocked.
- 🔄 Double memory consumption: applications are installed separately in each space.
- ⚠️ No synchronization: notifications and data (e.g. messages in messengers) are not duplicated.
- 🔧 Limited compatibility: Some banking applications can block work in the sandbox».
How to delete Second Space without losing data?
Method 3: Third-party applications for blocking
If the built-in MIUI tools don't suit you, you can use third-party utilities from Google Play.
- 🔒 AppLock (by DoMobile Lab): Supports password, fingerprint, lock Wi-Fi/geolocation.
- 🛡️ Norton App Lock: Integrated with antivirus, there is a function of “crack resistance».
- 📱 Smart AppLock: allows you to hide icons of blocked applications.
When choosing a third-party App Lock, pay attention to:
- 🔍 Permissions: Applications must not request access to SMS, Calls or geolocations without a reason.
- 📊 Rating and Reviews: Avoid Utilities with a rating below 4.0 and Advertising Complaints.
- 🔄 Compatibility: Some applications do not work MIUI 14 due to Xiaomi restrictions.
Critical feature: Third-party App Locks can conflict with MIUI system services, especially if Battery Optimization for Background Processes is enabled. To avoid spontaneous closure of the blocker, add it to the exceptions:
Settings → Battery and Performance → Battery Optimization → Select Apps → Find AppLock → Disable OptimizationBuilt-in App Lock
Second Space
Third-party AppLock
Not defending.
Another option-->
Comparison of application blocking methods
| Criteria | App Lock (MIUI) | Second Space | Third-party AppLock |
|---|---|---|---|
| Level of protection | Medium (depending on password) | High (complete isolation) | Different (depending on the application) |
| Impact on productivity | Minimum | Significant (double annexes) | Medium (background processes) |
| Compatible with MIUI 14 | Complete. | Complete. | Partial (possible bugs) |
| Recovery of access | Through Mi Account. | Just a phone reset. | Depends on the application (often not) |
| Additional functions | Hiding notices | Data isolation | Geodependence, disguise |
Second Space offers maximum protection but requires more resources, and the built-in App Lock is optimal for most users, and third-party solutions should only be considered under specific requirements (e.g. geolocation lock).
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For banking applications and instant messengers, it is better to use Second Space - it protects against data leaks through MIUI system vulnerabilities.
Frequent Mistakes and How to Avoid Them
When setting up app lock, Redmi Note 9 users often face typical problems:
- App Lock does not ask for password: Reason: Show password when you start in App Lock settings. Solution: go to Settings → App Lock → Settings (cogs) → Enable password request.
- Second Space is not created: Reason: there is not enough memory on the device (requires a minimum of 2-3 GB of free space), Solution: clear the cache or transfer files to the memory card.
- Third-party AppLock crashes: Reason: MIUI kills background processes. Solution: add the app to battery optimization exceptions (see instruction above).
⚠️ Note: If you use Root rights or custom firmware (such as LineageOS), the built-in App Lock and Second Space features may not work properly, and it is recommended to use third-party solutions that support Magisk (such as AppLock by IvyMobile).
Additional security measures
App passwords are only part of the protection. To keep your data as secure as possible on the Redmi Note 9, follow these steps:
- 🔐 Set up two-factor authentication for Mi Account (in Settings) → Xiaomi account → Security).
- 📱 Turn off notifications on the lock screen: Settings → Notifications → On the lock screen → Hide the contents.
- 🔄 Update regularly MIUI — In new versions, vulnerabilities are closed that allow you to bypass the lock.
- 🛡️ Use device encryption (in Settings) → Additionally. → Encryption and credentials).
It is also useful to set up automatic screen lock after 30 seconds of inactivity:
Settings → Lock screen → Sleeping on timeout → 30 seconds💡
If you often pass your phone to colleagues or friends, create a guest mode in MIUI: Settings → System → Guest mode, which will only have basic functions (calls, camera) available, and personal data will remain hidden.