Xiaomi Mi 9, which was released as a flagship device, is still popular due to its excellent screen and performance. However, over time, any Android gadget, regardless of its initial power, begins to accumulate temporary files that can significantly slow down the system. Users often notice that the phone warms up, apps open longer than usual, and free space in storage mysteriously disappears.
The main cause of these problems is often overgrown app cache and system temporary files. These are not viruses or critical errors, but normal operating system results, which, however, require periodic intervention. In this article, we will discuss in detail all the available methods of cleaning the cache on Xiaomi Mi 9, from standard MIUI tools to advanced methods through the engineering menu.
Regular maintenance of the device’s memory is not just a way to free up a couple of gigabytes, but a necessity to extend the life of the drive. Proper cleaning avoids program conflicts and ensures stable operation of the interface. Next, we will look at step-by-step algorithms that will help you return your smartphone to its former agileness.
Understanding Cache Types in Android System
Before we take action, we need to be clear about what we're going to fight. There are multiple layers of temporal data in the Android ecosystem that power the MIUI shell, and mixing these concepts can lead to the deletion of important information or, conversely, to inefficiency of the procedure.
The first is the app cache, and every program installed, whether it's a social network, a browser, or a navigator, saves temporary files to make it work faster, like Instagram storing thumbnails of the photos you've viewed, and the browser storing copies of the pages you've visited, and this type of data is safe to delete, because the apps will recreate it if necessary.
The second type is the system cache, which includes data from the operating system itself and Google services preinstalled. It is often required to be cleaned after major software updates or cyclic errors. The third type is the Dalvik/ART cache, which is an optimized application code for a specific processor. Deleting the Dalvik cache on the Xiaomi Mi 9 is safe, but the first system start after this procedure will take much longer than usual.
⚠️ Caution: Clearing the cache does not delete your personal photos, contacts or correspondence in messengers. However, clearing the data (not to be confused with the cache) of the application will lead to a complete reset of its settings and log out of the account.
Understanding the difference between these types of files will allow you to choose the most appropriate cleaning method in a particular situation.
What is the difference between cleaning the cache from reset to factory settings?
Basic cleaning through built-in Security application
The easiest and safest way to free up space on the Xiaomi Mi 9 is to use a regular developer tool. The MIUI shell is equipped with a powerful Security app that automatically analyzes memory status and suggests removing debris, a method suitable for regular preventive maintenance.
To start the procedure, look for an icon on your desktop called "Security" (green shield), launch the application and wait for the automatic scan to be completed, the system will check the installed programs for malicious code and analyze the amount of debris occupied.
After the analysis is complete, click the Clean button, and the system will prompt you to delete temporary files, deleted applications and advertising debris. Unlike third-party utilities, the built-in tool knows the specifics of MIUI and will not delete critical system files.
☑️ Checking before cleaning
It is important to note that the built-in cleaner does not always find all temporary files of third-party applications, as some of them can be hidden or protected.
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The built-in Security application is the most reliable way to quickly clean for ordinary users, without requiring deep technical knowledge and without carrying risks to the stability of the system.
Deep Cache Cleaning of Individual Applications
If the smartphone is slow only in certain programs, for example, slows YouTube or hangs Telegram, it makes sense to do a spot cleaning.The garbage in such applications can take up gigabytes of space, since media files are often cached for quick re-view.
To do this, go to your device's Settings menu. Find the Apps section and select All Apps. In the list that opens, find the problem program. For example, if you want to clear your browser cache, look for Chrome or the built-in MIUI browser.
Inside the app card, click on the Memory (or Storage) button. You'll see two main buttons: Clear cache and Clear all. The first deletes temporary files, the second resets the app to a state immediately after installation. Beware: the Clear All button will require you to log in again.
- 🗑️ Cash: Deletes temporary files without affecting logins and settings.
- 🧹 Data: Resets the application completely, removing correspondence (if there is no cloud sync) and authorization.
- ⚙️ Control: allows you to disable the application auto-start, which also saves resources.
- 📉 Size: Shows the actual weight of the application on the disk at the moment.
In Viber or WhatsApp, the cache can take up to 10-15 GB if you actively share media. Clearing the cache in these applications through the Android settings is safe for correspondence history, but will delete thumbnails and temporary files.
Cleaning the system cache through Recovery Mode
In cases where the phone is unstable, the interface is buggy or there are problems after updating the firmware, it is recommended to clean the system cache through the recovery mode.
To enter Recovery mode on Xiaomi Mi 9, you need to turn the device off completely. Then press the volume button and the power button at the same time. Hold them until the Mi logo appears, after which the phone will go to the Recovery menu. The volume buttons control the device, and the choice is confirmed by the power button.
Select a language (if available) or immediately look for Wipe Data. This menu often hides the option Wipe Cache. It is important not to confuse it with Wipe All Data, which will perform a full reset. Select cache clearing and confirm the action.
The sequence of actions in Recovery:
1. Turn off the phone.
2. Clutch Volume Up + Power.
3. Select a language (English).
4. Press Wipe Data -> Wipe Cache.
5. Confirm and wait for completion.
6. Select Reboot.⚠️ Attention: On new versions MIUI The option of separate cache cleaning in Recovery can be hidden or combined with a full cleanup.If you only see "Wipe All Data", it is better to refrain from action in this menu, unless you are planning a full reset.
Once the procedure is complete, the phone will restart. The first run can last up to 5-10 minutes, as the system needs to recreate the necessary temporary files. Don't panic if the screen is lit with the logo for a long time - this is normal process.
Using Developer Mode to Clean Dalvik
For advanced users who want to perform the deepest optimization, the developer mode is available. This section hides tools for working with the ART runtime, which is responsible for running applications in the Android environment.
To activate Developer Mode, go to Settings → About Phone. Find the MIUI Version string and quickly click on it 7-10 times in a row. The system will tell you that you have become a developer. Then a new section "Additional" → "Developers" will appear in the settings menu.
Inside this section, look for a item that cleans the startup profile or Dalvik cache. On some firmware versions, this feature is called "Clear Start Profile Data," which will force all applications to recompile the next time they boot, which can fix bugs in their work.
| Parameter | Description | Impact on the system |
|---|---|---|
| Cash app. | Temporary programme files | Frees up space, speeds up launch |
| System cache | OS and service files | Eliminates systemic glitches |
| Dalvik/ART | Optimized code | Fixes conflicts, long first download |
| Application data | Settings and logins | Complete reset of the program (not cache!) |
If you are not sure about your actions, it is better to limit yourself to a standard cleaning through settings, since forced code recompilation on an old device can temporarily reduce performance in the first hours after the procedure.
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After cleaning the Dalvik cache or startup profile, allow the phone to lie on a charge with the screen off for about 30-40 minutes.
Automation and pollution prevention
To avoid returning to the issue of cache cleaning on Xiaomi Mi 9 too often, it makes sense to configure automatic processes. Constant memory control allows you to maintain a high speed of the device without manual intervention.
In the Security app, you can set up a cleaning schedule. Go to the cleaning device settings (broom or gear icon) and turn on the "Clean Automatically" function. Select a frequency, such as once every 3 days or once a week. It is also recommended to turn on a notification when more than 80% of memory is occupied.
Also, it is worth rethinking the usage of messengers, which in the settings of Telegram, WhatsApp and Viber, you can limit the automatic saving of media files to the gallery, which will prevent duplication of cache in the main memory of the phone.
- 📅 Schedule: Set up auto-cleaning for nighttime when the phone is not in use.
- 🚫 Autoboot: Turn off autoload media in chat rooms to save traffic and space.
- ☁️ Cloud: Use Google Photos or Mi Cloud to store archives by removing them from your device.
- 🔄 Updates: Keep apps updated as newer versions often manage cache better.
Regularly restarting your phone at least once a week also helps the system to reset accumulated errors in RAM and clear some temporary files that are not deleted during normal operation.
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The best maintenance strategy is a combination of automatic weekly cleaning with built-in tools and manual control of heavy applications like instant messengers and social networks.