Modern smartphones, even budget models like Xiaomi Redmi 9, inevitably slow down over time. The main reason for the drop in performance lies not in the aging of the hardware, but in the accumulation of digital garbage: application caches, residual files of uninstalled apps and duplicate photos. Standard cleaning methods often affect only the surface layer, leaving gigabytes of hidden junk that slows down the system. Manual cleaning is the most effective way to return the device to its former agility, but it requires care and understanding of the file system structure. MIUI.
Manual cleaning is the most effective way to restore the device to its former agility, but it requires care and understanding of the file system structure Android. In this instruction, we will look at how to safely remove unnecessary data without damaging important data. You will learn how to find hidden folders, clear the cache of system services and optimize storage without installing third-party software.
Preparing a file manager and access to the system
The first step before starting "spring cleaning" is to ensure access to all directories of the device. The standard shelled explorer MIUI is quite functional, but for deep cleaning it is better to use specialized tools or enable the display of hidden files. Go to the Explorer settings and activate the option Show hidden filesto see folders starting with a dot.
Many users ignore this step, relying on automatic cleaners, which often offer to delete the necessary files for the sake of statistics. The manual method allows you to personally control each byte that is deleted. Before starting manipulations, it is strongly recommended to create a backup copy of important contacts and photos in cloud storage or on your computer.
⚠️ Attention: Never delete files from folders
Android/dataorAndroid/obbentirely, unless you are 100% sure that they belong to deleted games. This may lead to loss of saves or inoperability of installed applications.
Before deleting any system files, take a screenshot of the folder structure - this will help restore the path if you accidentally delete something unnecessary.
For advanced users, it is possible to connect the smartphone to the PC in debugging mode, but for basic manual cleaning of Redmi 9, the built-in tools are quite sufficient. The main thing is to act consistently and not delete anything the purpose of which is unknown to you.
Analysis and cleaning of the Download and Downloads folder
The most obvious place where garbage accumulates is the downloads directory. Browsers, instant messengers and email clients often save installation files here APK, documents and pictures that were needed only once. Go to the file manager and open the folder Download. There are often old versions of applications that you have already updated, but the installers remain dead weight.
Particular attention should be paid to files with the extension .apk. If the application is already installed and running, the installation file is no longer needed. Removing it will free up space, but will not affect the operation of the app. Also check the folder for temporary documents in formats PDF or DOCXthat you downloaded months ago for reference.
- 🗑️ Delete all installation files
.apkif the corresponding applications are already running. - 📄 Check the archives
.zipi.rar—often they contain already unpacked data. - 🖼️ Sort the files by size and delete the heaviest videos or documents that are no longer relevant.
Do not forget that some instant messengers, for example Telegram or Viber, can duplicate received files in the general download folder, creating confusion. Look carefully at the modification date of the file: if it is older than six months and you have not opened it recently, most likely it is no longer needed.
Working with the cache of applications and system services
Cache is temporary data that applications save to speed up their work. Over time, the cache can grow to gigabytes, especially in social networks and browsers. Unlike user data, the cache can be deleted painlessly, although the application may reload the information a little when you first launch it. For manual cleaning, go to Settings → Applications → All applications.
Select the most "heavy" apps, such as YouTube, Instagram, Chrome or TikTok. Inside the menu of each application, find the item Storage and press the button Clear cache. It is important not to confuse this button with the “Clear all” or “Erase data” option, as it will delete your logins, passwords and settings within the application.
| Application type | Approximate cache size | Wipe frequency | Risk of data loss |
|---|---|---|---|
| Browsers | 200 MB - 1 GB | Once a week | Low (history visits) |
| Social networks | 500 MB - 2 GB | Once a month | Low (re-login required) |
| Games | 100 MB - 5 GB | Rarely | Medium (graphics settings may go wrong) |
| Messengers | 100 MB - 1 GB | Caution | High (media from chats may be deleted) |
System services also accumulate temporary files. This is especially true for the service Google Play Services and system component MIUI. Clearing their cache often solves problems with the interface freezing or notifications not working correctly. Do this carefully, selecting the “Cache” item and not “Data”.
Clearing the cache does not delete your personal accounts and correspondence, it only resets temporary image and script files, speeding up the application.
Search and delete duplicate media files
Camera smartphone Redmi 9 creates not only basic pictures, but also many service thumbnails and sketches. These files are stored in hidden folders and take up a significant amount of memory. The largest amount of garbage is usually concentrated in the directory DCIM →.thumbnails. This folder is hidden by default, so you had to enable the display of hidden files in the first step.
The files in the folder .thumbnails are small copies of your photos and videos that the gallery uses for quick previews. Over time, this folder can grow to several gigabytes. You can safely delete all the contents of this directory manually. The system will automatically re-create the necessary thumbnails the next time you open the gallery, but old “tails” from deleted photos will disappear forever.
⚠️ Attention: When opening the gallery for the first time after clearing the folder
.thumbnailsthe phone may work slowly and heat up. This is a normal process of re-creating thumbnails, it will complete in 10-15 minutes.
It is also worth checking the folder Pictures and the root of the internal memory for duplicates. Often users save the same image from different sources (WhatsApp, browser, camera) without noticing it. Visual inspection and sorting by size will help identify copies that weigh the same and have similar names.
Why is the .thumbnails folder growing again?
The .thumbnails folder will grow again as new photos are added. This is an Android system feature for gallery performance. It is recommended to clean it once every 2-3 months, rather than deleting the folder itself forever.
Cleaning garbage from instant messengers (WhatsApp, Telegram, Viber)
Messengers are the main memory hogs on any Android smartphone. They automatically save every photo, video and voice message received into a separate folder on the device. Even if you delete a chat message, a media copy of it often remains in the phone's memory. For WhatsApp the path usually looks like Android/media/com.whatsapp/WhatsApp/Media (on new versions of Android) or simply WhatsApp/Media at the root.
Inside the folder Media pay attention to the subfolders WhatsApp Images i WhatsApp Video. Thousands of unnecessary pictures from group chats, postcards and statuses often accumulate here. Manually deleting them takes a long time, so you can use sorting by date and delete everything older than a certain period. The situation is similar with Telegramwhich stores the cache in a folder Telegram/Telegram Images.
- 📹 The folder
WhatsApp Videousually takes up the most space due to the transfer of videos. - 🎙️ Don't forget to check the folder
WhatsApp Audio, where voice messages and music are stored. - 📁 In Telegram you can enable automatic cache clearing in the settings of the application itself, which is more convenient than manual cleaning.
Be careful with the folder Private inside messenger directories. Files that you have hidden from public access go there. Before mass deletion, make sure that there are no important documents or personal photos that you do not want to lose.
☑️ Cleaning messengers
Deleting residual files after uninstallation
When you delete an application via standard Android interface, it often leaves behind “traces” in the form of empty folders or configuration files. These balances do not take up much space individually, but can add up to hundreds of megabytes. They are usually located in the root of the internal memory and are named after deleted apps or developers.
Find folders with the names of games or utilities that you have long deleted. For example, if you played some game from Gameloft or used a photo editor, the folder with the brand name may remain empty or contain only error logs. Feel free to delete such directories if you are sure that the app is no longer installed.
Pay special attention to the folder Android/data. Application-specific data is stored here. If you deleted a game, but its folder with the name of the package (for example, com.example.game) remains and takes up gigabytes, this is an obvious candidate for deletion. However, if you plan to reinstall the application and save your progress, it is better to leave these files.
⚠️ Attention: The folder access interface
Android/datamay be limited in new versions of Android for security reasons. If the file manager does not allow you to delete files from there, try connecting your phone to a PC or using a specialized file manager with extended rights.
Use the search in the file manager by entering the names of deleted applications. This is faster than manually going through all the folders in the root memory.
System optimization and completion of cleaning
After you have deleted all unnecessary files manually, you need to reboot the device. A reboot is needed so that the system Android correctly recalculates the free space and updates the media file indexes. Without this step, the gallery may display “ghost” albums or an incorrect value of free memory in the settings.
To maintain cleanliness in the future, it is recommended to repeat the procedure of cleaning the folder .thumbnails and the cache of heavy applications once a month. It is also worth disabling autosaving of media files in the messenger settings so that they do not clog up your memory without your knowledge. Redmi 9 it is also useful to use the built-in "Security" application to scan for viruses after manual cleaning.
Regular maintenance of the file system extends the life of the smartphone's drive, since flash memory works more stable when it is not jammed to capacity. Leave at least 10-15% of free space for the system to operate correctly and install updates.
Regular manual cleaning is more effective than automatic cleaning, since you control the process and do not risk deleting important system files due to an algorithm error.
Is it possible to delete the entire Android folder?
Categorically no. Deleting the entire folder Android will lead to resetting all applications to factory settings, loss of game data and system malfunction. You can only delete specific subfolders inside data or obbthat relate to already deleted apps.
Why is the space not freed up after cleaning?
You may have cleared only the cache and not deleted the files. Also check the Recycle Bin in the gallery and file manager - deleted files are often stored there for another 30 days, taking up space. Empty the trash to actually delete data.
Is it safe to use third-party cleaners on Redmi 9?
Most popular cleaning applications (Clean Master and analogues) actually only duplicate the functions of the system, but show a lot of advertising and can themselves slow down the phone. Built-in MIUI tools and manual cleaning are safer and more effective.
How to find the largest files on your phone?
In standard Xiaomi Explorer, click on the menu (three bars) and select "Storage Analysis" or sort files in any viewing mode by the "Size" parameter. This will immediately show the heaviest videos and archives.