By default, Xiaomi Redmi 9 smartphones allow you to install applications from third-party sources – the so-called APK-This feature is useful for testing betas or installing programs that are not available on Google Play, but also opens the door to viruses, spyware and fraudulent utilities. According to Kaspersky, more than 30% of Android malware is distributed through manual installation. APK, bypassing official shops.
If you hand over your phone to your child, use it to work with sensitive data, or just want to minimize the risks, blocking the installation from unknown sources becomes a must. In this article, we will discuss all ways to disable the function on Redmi 9 (including Redmi 9A/9C/9T models), taking into account the features of the firmware MIUI 12, 13 and 14.
⚠️ Important: After blocking, you will not be able to install APK-files downloaded from the browser or sent via instant messengers, if you need to temporarily allow installation (for example, for the purpose of ADB-commands or debugging purposes), use the application-specific exception method described below.
Why you should ban APK installation from unknown sources
The main threat is not in themselves. APK-The official stores (Google Play, Mi App Store) check apps for viruses and compliance with security policies:
- 🦠 Malware: Trojans, mining scripts, or spies masquerading as legitimate programs (such as modified versions of WhatsApp or games).
- 🕵️ Data Collection: Apps may secretly transfer your geolocation, contacts, or message history.
- 💸 Fraud: Fake banking applications or clones of popular services (e.g. SberBank Online with a modified interface).
- 🔄 Unstable work: Unoptimized APK can cause system failures, overheating or rapid battery discharge.
According to Avast, in 2023, one in five Android users installed APKs from unverified sources at least once, and 12 percent of them faced consequences from ad viruses to account theft. Xiaomi is at higher risk due to the popularity of the brand in regions with active pirated software distribution.
⚠️ Note: Even if you are downloading APK From a "reliable" site (e.g., APKMirror), there is no guarantee that the file was not swapped on the server or during transmission (MD5/SHA-1) file with official, but it requires technical skills.
Method 1: Complete shutdown via security settings
The most reliable method is to globally disable the APK installation from unknown sources, and the instructions are relevant for MIUI 12-14 (including HyperOS):
- Open the settings (cog icon on the desktop).
- Go to the Appendix section → Application management.
- Click on the three dots in the top right corner and select Special Access.
- Slip on the item Install unknown applications.
- In the list of applications (browsers, file managers) disable sliders opposite each.
✅ The system will then block all installation attempts. APK, If you try to open a file, it will be notified, "Installation locked. Allow installation from this source in the settings".
☑️ Checking the locking of the installation APK
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If the Unknown App Installation list does not have the right app (e.g. Telegram), it has not yet tried to install APK. The slider will appear automatically when you first try to install it.
Method 2: Exceptions for Trusted Applications
If you only need to allow APK installation from specific sources (like F-Droid or enterprise portal), use selective permission.
Instructions:
- Follow the steps from Method 1 to 4 (Install Unknown Applications).
- Find the app you want to make an exception to (e.g. Chrome or Mi Browser).
- Turn on the slider in front of it. A warning will appear, press Allow.
- Repeat for other applications if necessary.
⚠️ Note: By allowing installation for the browser, you automatically allow installation of all APK, It means that the malicious file downloaded from the link in the VK We recommend using this method only for specialized applications (for example, F-Droid), where the risk of file swapping is minimal.
Method 3: Blocking through parental control (for children)
If a child is using a phone, turning off the APK installation is not enough, because children often find workarounds, and in this case, parental control in MIUI, which allows:
- 🔒 Block the installation of any applications without a password.
- 📱 Restrict access to Settings so that the child cannot turn the installation back on.
- ⏰ Set limits on the use of specific programs.
How to set up:
- Open the Settings. → Parental control.
- Create a child profile (you will need to link your Mi Account).
- In the Restrictions section, select Install Applications and set the Restriction Forbidden.
- Ask. PIN-Unlock code (do not use simple combinations like 1234!).
What to do if the child has reset the settings?
Problem Solving: What to do if the settings are not saved
Sometimes, after you turn off the APK installation, the sliders in the settings are reset or the system still allows you to install files.
| Problem. | Possible cause | Decision |
|---|---|---|
| Sliders automatically turn on | A virus or optimizer (such as Clean Master) resets settings. | Remove suspicious apps, check your phone with antivirus (Dr.Web or Malwarebytes) |
| Settings are not available (grey text) | Device policy is active (for example, through Android Enterprise) | Contact the administrator or delete the job profile in Settings → Accounts |
| APK is installed despite the lock | ADB or superuser rights (root) are used | Turn off USB debugging in Settings → For developers and remove Magisk/SuperSU |
| Error "Package not installed" | Conflict with the existing version of the application | Remove the old app through Settings → Apps and re-install |
If the problem persists, reset your security settings:
- Go to Settings → About the phone → Reset settings.
- Select Reset Application Settings (does not affect personal data).
- After restarting, repeat the lock setting.
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If the phone is connected to a corporate network (e.g., via Microsoft Intune), the administrator can remotely change the security settings, in which case the APK lock will be reset as long as the policy is active.
Additional security measures for Xiaomi Redmi 9
The APK ban is only part of the protection, and for complete safety on Redmi 9, we recommend:
- 🔐 Disable debugging by USB: Go to Settings. → For developers and deactivate the debugging by USB. This will prevent the installation of software through ADB.
- 🛡️ Install antivirus: Free versions of Bitdefender or Avira scan APK before installation.
- 🔄 Update MIUI: New firmware versions close vulnerabilities that allow you to bypass locks. Check the updates in Settings → The phone. → Updating the system.
- 📲 Use Safe Folder: In MIUI There is a Safe Folder function (in Settings) → Privacy, which encrypts files and blocks access to them without a password.
⚠️ Attention: Redmi 9 with firmware MIUI 12.5 and below, there is a bug: after updating through Recovery, the security settings are reset.Be sure to write down the current lock settings before updating or backup through Settings. → Additionally. → Backup.