The Xiaomi Mi 9S (often known globally as the Redmi K20 Pro) is a powerful device capable of handling most modern tasks even years after its release. However, like any complex electronics, it has the ability to accumulate digital debris during active use. Users often notice that over time the interface slows down, applications open longer, and memory space disappears rapidly. The main cause of such problems is the sprawling cache, temporary files that the system and programs save to speed up their work.
Temporary data is a natural process, but uncontrolled growth can cause malfunctions in the Android operating system and the MIUI shell. Cache can take up gigabytes of space, blocking the installation of new updates or simply preventing new photos. In this guide, we will discuss in detail how to safely and efficiently clear the cache on your device, returning it to its previous response speed.
It is important to understand that cleaning the cache is not the same as a full reset to factory settings.You will not lose your contacts, photos or installed apps if you follow the instructions correctly.We will look at both the standard system tools and more advanced methods available to owners of the Xiaomi Mi 9S. Proper memory maintenance extends the life of the drive and ensures the stability of the gadget in the long run.
What is cache and why it should be cleaned on MIUI
Cache is a buffer memory that stores the temporary files needed to quickly load commonly used interface elements and content. When you open an application for the first time, the system downloads all the resources from the disk, which takes time. When you restart, data is taken from the cache, which happens almost instantly. However, if the cache algorithms fail or files are corrupted, it leads to the opposite effect - slowing down.
The MIUI shell on the Xiaomi Mi 9S has its own features: it aggressively caches data to ensure smooth animations, but over time this “stock” becomes too large and inefficient, especially for social networks and browsers that store huge amounts of media content. Regular cleaning allows you to free up space and eliminate errors caused by the conflict of old and new versions of files.
⚠️ Warning: Cache should not be fanatically cleaned every hour. Excessive deletion of temporary files can make the processor and drive work harder, re-creating the necessary data structures, which sometimes leads to increased battery consumption.
There are several types of cache that you should distinguish before starting a procedure: the system cache affects the operation of the operating system itself, the application cache is specific to programs, and the browser cache contains web page data. Understanding this difference will help you choose the most suitable cleaning method for your particular situation.
Cleaning the cache through the standard Security app
The easiest and safest way to free up space on the Xiaomi Mi 9S is to use a built-in system tool. Every smartphone with a MIUI shell has a Security app (a green shield icon) preinstalled, which includes a powerful memory analyzer, which scans the device for junk files, residual data from remote programs and bloated cache.
To get started, you need to launch the app and click on the large Cleanup button, and the system automatically scans all memory partitions and gives you a list of files that can be deleted without damaging personal data, which usually takes no more than 10-15 seconds thanks to the fast Snapdragon 855 processor installed in the Mi 9S.
☑️ Cleaning Algorithm Through Security
Once you've finished scanning, you'll see the amount of debris you find, and if you click on the cleanup button, you'll delete the temporary files, but if you want to clean it up a little bit deeper, you'll need to go to the in-app garbage cleaner and look at the categories, and you can select the app cache, the ad files, and the installer packages that are often left in the system.
The use of the standard tool ensures compatibility and no conflicts with the system. Unlike third-party programs, the built-in cleaner has the necessary permissions to work with the Android system partitions, which allows you to delete files that are not available for ordinary applications from the Google Play store.
Deep Cache Cleaning of Individual Applications
Often, the bulk of memory is not the system files, but the data of specific applications, such as Telegram, WhatsApp, Instagram or TikTok. These programs store a huge number of images and videos, which are formally cache, but can be important to the user, to manage them, you need to go to the settings of the smartphone.
Navigating to the menu you want is done by Settings → Applications → All apps. In the list that opens, find the leader program for memory consumption. Inside the app menu, you're interested in Memory or Storage. There you'll see two buttons: Clear and Delete. It's important not to confuse them.
- 💣 The Remove (or Reset) button completely erases all application data, returning it to state immediately after installation.
It is characteristic of the Xiaomi Mi 9S that some system applications can also accumulate cache, such as Google Play services or the MIUI theme store. Cleaning them often solves problems with the inability to download updates or install new wallpapers. If you notice the strange behavior of a particular program, cleaning its cache is the first step in diagnosis.
⚠️ Note: When cleaning the messenger cache through the system settings, you will not lose correspondence, but saved thumbnails of images can be cleared, which will be loaded again when viewed, consuming traffic.
It is recommended to regularly check the most "heavy" applications. In today's conditions, social networks can grow to several gigabytes. Clearing the cache of such applications can instantly free up 2-3 GB of free space, which is critical for the stable operation of the Xiaomi Mi 9S, especially if you have a version with 64 or 128 GB of internal memory.
Use of Recovery Mode (Recovery Mode)
A more advanced method to clean the system cache at a deep level is to use Recovery mode, which is loaded separately from the main operating system and provides access to service functions. On Xiaomi Mi 9S, it is a safe procedure if you perform actions consistently and do not choose unnecessary options.
To enter the recovery mode, you need to turn off the smartphone completely. Then you need to press the key combination: the on button and the volume button (Power). + Hold them at the same time until the Mi logo or Recovery menu appears. Depending on the firmware version (Chinese or global), the menu can be in English or Chinese.
What to do if the menu is in Chinese?
In the menu, you can navigate with volume buttons (up/down), and the choice is confirmed by the power button. You need to find Wipe Data. Within this menu, you will have the Wipe Cache option. This is the one you need to select. Once confirmed, the system will clear the temporary Dalvik files and the system cache.
This method is especially useful if the smartphone is unstable, there are cyclical reboots or hanging on the logo.Cache clearing through Recovery does not affect user files (photos, contacts), unlike a full reset of Wipe All Data, so it is a safe first aid tool for the Mi 9S.
Storage analysis and work with files
Sometimes standard methods don't show what's eating up the space, and in those cases, the built-in storage analyzer comes to the rescue, and in MIUI, it's available via the Settings → Memory path, or through the Explorer app on the Analysis tab, and this tool visualizes (occupied space) by showing a file distribution diagram.
You can find forgotten downloads, duplicate photos or cache of remote applications. The Xiaomi Mi 9S file system allows you to quickly sort files by size. Often, it turns out that half of the memory is occupied by videos from messengers that were automatically saved to the gallery.
| Type of data | Wherever | Can I remove it? | Impact on the system |
|---|---|---|---|
| Cash app. | Settings / Applications | Yes, it's safe. | Accelerating work |
| File.thumbnails | DCIM /.thumbnails | Yeah, but it'll grow back. | Frees up a lot of space. |
| Android/Obb folder | Internal memory. | Only for remote games | Can break games. |
| System cache | Recovery Mode | Yes, it's safe. | Solves loading errors |
The.thumbnails folder in DCIM directory is a hidden folder that stores thumbnails of your photos for quick display in the gallery, and over time, this file can grow to several gigabytes, and can be safely deleted through the file manager by enabling the display of hidden files.
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To prevent the.thumbnails folder from growing back to giant sizes, you can create a text file called.thumbnails in the DCIM root folder and set it to Read Only, which will prevent you from creating a new large thumbnail file.
Automation and third-party utilities
For those who don’t want to keep a clean manual, there are ways to automate the system: In the settings of the Security app on the Xiaomi Mi 9S, you can set up an automatic cleaning schedule, the system will scan and remove debris at a given time, for example, at night when the phone is not in use.
If there is not enough regular funds, you can turn to proven third-party solutions. However, when installing cleaners from Google Play, you should be extremely careful. Many of them contain aggressive advertising or are themselves sources of garbage. Files by Google or SD Maid (for advanced users) are considered the best options.
- 🚀 Files by Google is Google’s official app that safely analyzes memory and suggests removing duplicates and debris.
- 🧹 SD Maid is a powerful tool for deep cleaning of residual files after deleting applications (requires careful study).
- 🛡️ CCleaner is a popular cleaner, but the free version can be intrusive with notifications.
The use of third-party software on MIUI is often limited to the system itself. Xiaomi’s shell strictly controls background processes and can block cleaners if they try to get too many permissions. Therefore, a bundle of “staff cleaner + manual check of heavy applications” often proves to be more effective than any third-party harvesters.
⚠️ Warning: Avoid installing accelerators RAM" On modern versions of Android, they are not only useless, but also harmful, because they constantly restart system processes, loading the Snapdragon processor.
Frequently Asked Questions (FAQ)
Is it safe to clear the cache of all apps right away through settings?
Why did the phone start to work slower after cleaning the cache?
Do I need to reset to factory settings if the cache doesn't help?
Can a crowded cache damage the screen or battery of the Mi 9S?
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Regularly cleaning the cache is a prevention, not a panacea. If the phone brakes even after cleaning and restarting, the problem could be battery wear or hardware malfunction.
To sum up, the Xiaomi Mi 9S has great self-service tools. By combining built-in Security, manual cleaning of heavy apps, and periodic storage analysis, you can keep your smartphone in perfect condition for years, and the key is not to get carried away with deleting system files and understand the difference between cache and important data.