How to put a password on the application in Xiaomi Redmi Note 9: official and hidden methods

Xiaomi Redmi Note 9 remains one of the most popular smartphones of the brand due to the balance of price and performance, but its owners often face the problem: how to protect personal data in applications from prying eyes? Unlike flagship models, where the App Lock feature is available out of the box, in basic versions of MIUI for Redmi Note 9 it can be hidden or absent. In this article, we will examine all the working methods, from standard tools to workarounds using Second Space and third-party applications.

The Redmi Note 9 (M2003J15SC/M2003J15SS) is a regionally-dependent firmware feature, for example, in the global version of MIUI, the application lock function can be disabled by default, whereas in the Chinese version of the ROM, it is available immediately. We tested all methods on current versions of MIUI 12.5-14 and identified those that work stably. Importantly, some methods require unlocking the bootloader or root rights, we will warn you about this in advance.

1. Standard App Lock: Where to look and how to turn on

The most obvious way is to use the built-in App Lock feature, but in the Redmi Note 9, it can be hidden or not in the security menu.

1. Open the Settings. → Password and security.
2. Scroll down to Privacy, where it should be Application Block, and if it's not, move on to the next one.
3. When the system is first started, it will be asked to install PIN-You can choose a reliable option, you have to type it every time you open a blocked application.
4. In the list of applications, mark the ones you want to protect (for example, WhatsApp, Gallery, Bank clients).

If there is no Block Apps, then your version of MIUI does not support it, as is typical of the European and Russian firmware Redmi Note 9 based on Android 10/11.

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If App Lock is not in the settings, try updating your firmware to the latest version of MIUI via Settings → About Phone → System Update. Sometimes the feature appears after an upgrade.

2.Second Space: Creating a Separate Protected Profile

Second Space is a feature built into MIUI that allows you to create a second user profile with separate apps and data, and all applications are password protected by default when you sign in, and this method is more reliable than App Lock, since it completely isolates personal data.

How to set up:

• 🔒 Go to Settings. → Special facilities → Second Space.
• 📱 Click Create Second Space and follow the instructions. The system will prompt you to copy applications from the main profile or install them again.
• 🔑 Set a password to log in to Second Space (it may differ from the phone's primary password).
• 🔄 Switch between swipe profiles down the lock screen (avatar icon in the upper right corner).

Advantages of the method:

• ✅ Complete data isolation – Second Space applications are not visible in the main profile.
• ✅ You can hide the very existence of the second profile (in the settings there is an option to Hide Second Space).
• ✅ It works even if the app lock is disabled.

Disadvantages:

• ❌ It takes up additional memory space (apps are duplicated).
• ❌ It is inconvenient to constantly switch between profiles.

Third-party applications for blocking: TOP-3 verified versions

If the standard methods don't work, third-party utilities will come to the rescue, and we've tested dozens of apps and selected those that are compatible with the Redmi Note 9 and do not conflict with MIUI:

How to install and configure (in the example of AppLock):

1. Download the app from Google Play and open it.
2. Set a master password (remember it!).
3. In the list of applications, select the ones you want to block.
4. In the settings (⚙️ → Advanced) enable Hide AppLock icon to hide the app icon.

Check the Android version (should be at least 9.0)

Download APK only from official sources (Google Play, APKMirror)

Turn off battery optimization for AppLock in MIUI settings

Create a backup of passwords in a secure location-->

⚠️ Note: Some blocking apps (such as AppLock) may conflict with MIUI Optimization. If lags or spontaneous reboots occur after installation, add the app to the exceptions: Settings → Battery → Optimizing the battery → Select applications → AppLock → Not optimize.

4. Hidden MIUI features: how to unlock App Lock through the test menu

On MIUI 12.0.2-12.0.7 firmware for the Redmi Note 9, there is an undocumented way to turn App Lock on through the engineering menu.This method doesn’t work on all devices, but if the standard settings don’t work, try:

1. Open the Phone app and enter the combination: ##4636##.
2. In the menu that appears, select Phone Information.
3. Scroll down and find MIUI Version, tap it 5-7 times until you become a developer.
4. Go back to the basic settings, open Additional → for developers.
5. Find the App Lock option (hidden) and activate it.

After that, the Password and Security menu should show up as "App Lock" -- if it doesn't, your firmware doesn't support this trick.

5. Blocking through Google Play Family Link (for parental controls)

If you need to restrict access to apps for a child or second user, you can use Google Family Link, which allows you to:

• 🔒 Block individual applications.
• ⏰ Establish time limits for use.
• 📊 View activity (which applications were launched).

How to set up:

1. Download Family Link to your phone (parent) and Redmi Note 9 (child).
2. Create a Google account for your child (if not) through families.google.com.
3. In the Family Link app, select your child’s profile, go to App Management and block unnecessary ones.

Limitations of the method:

• It only works for Google accounts under the age of 13 (or older if you have a family group previously).
• Does not block system applications (e.g. Settings or Gallery).

Problems and Solutions: What to Do When Your Password Doesn't Work

Redmi Note 9 users often encounter bugs when blocking applications. Let’s consider the typical problems and ways to solve them:

⚠️ Note: If you forgot your AppLock password and didn’t link your email to restore, the only way to reset the lock is to delete the app data through Settings. → Annexes → AppLock → Warehouse → Clear the data. This will remove all locks, but it will also remove the settings!

7.Alternative methods: encryption and hidden folders

If blocking apps is not appropriate, consider other ways to protect your data:

• 🔐 Encrypting Files: Use the ES File Explorer or Solid Explorer to encrypt folders with personal data (photos, documents). Example: in Solid Explorer, select a folder → Properties → Encrypt.
• 📁 Hidden folders: B MIUI You can hide files in the gallery: open the photo → ⋮ → Hide. Access to hidden files: Gallery → Albums. → Hidden (password protected).
• 🌐 VPN + private DNS: To block access to certain sites in applications (for example, in the browser), configure Settings → Connections → Private DNS (specify dns.google or 1.1.1.1).

For maximum protection, combine methods.

1. Create Second Space for personal applications.
2. Encrypt important files in your main profile.
3. Install AppLock on the remaining applications.

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The most reliable way is to combine Second Space (for data isolation) + AppLock (for blocking individual applications in the main profile).

FAQ: Frequent questions about blocking apps on Redmi Note 9