The Xiaomi Redmi Note 9, released in 2020, is still a popular device due to its excellent price-performance balance. However, over time, like any electronic device, it starts to run slower and the internal memory fills up with unnecessary files. It is a natural process of accumulating cache, residual files from remote applications and system debris that requires regular user intervention.
Proper cleaning not only frees up precious space, but also prolongs battery life, and also increases the overall stability of the MIUI operating system. In this article, we’ll look at all the effective ways to clean your phone, from built-in tools to radical resetting measures.
Before you start deleting files, it is important to understand which data can be touched without risk to the system, and which is better left alone. A competent approach will allow you to avoid accidentally deleting important contacts or photos, while maintaining a high speed of the gadget.
Memory Occupation Analysis and Garbage Search
The first step before any cleaning should be diagnostics, you need to understand exactly what is taking up space on your Redmi Note 9. Often users do not even suspect that half of the memory is occupied by forgotten videos in messengers or cache streaming services.
To start, go to the standard Security app, which is preinstalled in the MIUI shell. This tool automatically scans the device for temporary files, ad debris and uninstall residues. The system will prompt you to delete what it considers safe, but manual control will never interfere.
You can do a deeper analysis through the settings menu. Go to Settings → Memory to see a detailed breakdown by category: applications, images, video, audio, etc. System files usually occupy a fixed volume, and it is not recommended to touch them without root rights, as this can lead to unstable work.
And you can look at the Downloads folder, and that's where everything you download from the Internet is saved by default: the installations. APK-Files, documents, pictures, often contain files you needed six months ago.
Cleaning with the built-in Security application
The easiest and safest way to clean a Xiaomi Redmi Note 9 phone is to use the standard software. Xiaomi has built a powerful combine to maintain the system, which does not require the installation of third-party programs.
Run the Safety app (green shield icon) and you'll see the Cleanup button on the home screen, click on it, and the system will quickly scan it, and after the analysis is complete, the amount of debris found and the Clean button will appear on the screen.
However, standard cleaning only affects the surface layer. For more in-depth work, click on the Garbage icon in the bottom menu or select Deep Clean (if available in your version of MIUI).
- 🗑️ Application cache – temporary data that speeds up programs, but grows to gigabytes.
- 📦 Packages APK — Installation files of applications that are already installed and no longer needed.
- 📸 Similar photos – the system will offer to remove duplicate images taken in the serial shooting mode.
- 📄 Small files – lists of files smaller than 100 KB, which are often leftovers from programs.
💡
Don’t be afraid to delete the app cache through the built-in utility.This won’t result in loss of personal data such as correspondence or game progress, but will free up space.
It’s important to note that after cleaning the cache, some apps can open a little slower on the first run, which is normal, since the Redmi Note 9 re-forms temporary files for quick operation.
Manual cleaning of the storage through the Conductor
Automatic tools don't always see everything. Manually checking files through the built-in Explorer allows you to find and remove really heavy and unnecessary objects, and this is especially true for instant messenger folders.
Open the Explorer app and go to Files, and you should be interested primarily in DCIM (camera), Download (download) and social media folders. In modern Android versions, the path to messenger data may be hidden, but often it lies in the root or in the Android/media folder.
Pay special attention to the folders of messengers such as Telegram and WhatsApp, which tend to grow to incredible sizes, saving every video and picture you see.
- 📂 For Telegram, the path often looks like Android/data/org.telegram.messenger/files (Access can be restricted in new Android or a separate Telegram folder.
- 💬 For WhatsApp, look for the WhatsApp folder → Media → WhatsApp Images and WhatsApp Video.
- 🎵 Check the Music and Podcasts folder if you’ve listened to offline music.
⚠️ Note: When manually cleaning through Explorer, never delete files with the.obb or.data extension from the folders of installed games unless you want to lose progress or the games themselves. MIUI, Android (Inside System Logs), Xiaomi.
Deleting old screenshots is another easy way to free up space: The Screenshots folder is inside the DCIM or at the root of the memory. Often it stores hundreds of images that you took to show someone an error and forgot to delete.
Management of applications and their data
Apps are the main consumers of space on the Xiaomi Redmi Note 9, and over time they acquire data that may not be used for years, and they are managed through the settings menu.
Go to Settings → Apps → All apps. Sort the list by size (usually there is such an option in the three-dot menu), you will be surprised to find that a simple browser or news feed takes up several gigabytes.
Go to the information about the heavy app, and you'll see two important buttons: Clear and Delete. Clicking on Clear will offer two options: Clear cache and Clear everything (or Reset), Clear cache is safe, and Clean Everything will return the app to state immediately after installation by removing your logins and settings inside it.
☑️ Checklist for cleaning applications
Remember Google's system apps. Google Play services can store data. They can be cleaned, too, but with caution. Go to the settings of the Google Play Store app and select Clear Cache, which often solves the problems with downloading updates.
Removal of duplicates and large files
A smartphone often stores multiple copies of the same file, which can occur when you sync with the cloud, send files to yourself, or crash when you save them, and searching for duplicates is an effective cleaning method.
In the Security or Explorer app (depending on the MIUI version), there is a duplicate search function. If the built-in tools can't find them, you can use file sorting by size. In Explorer, select the size sorting (large to smaller).
Large files are often forgotten in the download folder, which can be forgotten movies, document archives or update installers, and deleting a 1.5GB file will instantly free up a significant portion of your Redmi Note 9’s memory.
It's also worth checking the Gallery cart, and when you delete photos and videos, they don't disappear forever, but they go to the Deleted album, which is stored for 30 days, and to finally clean your phone, you go to the Albums, scroll down to Deleted and clean them there.
Resetting to factory settings as a radical method
If the software cleaning doesn’t work, the phone is slow, buggy, or you just want to sell the device, the last option is a full reset.
Critical: Before you do this, you need to back up all your important data, you can't recover deleted files without a backup, use the Mi Cloud, Google Drive, or transfer the photo to your computer.
What happens when you reset your settings?
To perform the reset, go to Settings → About Phone → Reset. Select “Erase All Data.” The system will ask you to enter the unlock password and the Mi Account password (if you have theft protection enabled). Once confirmed, the phone will restart and the cleanup process will begin, which can take 10-15 minutes.
| Cleaning method | Security | Efficiency | Risk of data loss |
|---|---|---|---|
| Cache cleanup (Security) | Tall. | Low/Mediocre | No. |
| Manual deletion of files | Medium | Tall. | There is (if you remove the excess) |
| Cleaning up application data | Medium | Medium | Local settings of the application |
| Reset to factory settings | High (for the system) | Maximum | Total data loss without backup |
⚠️ Warning: Don't interrupt the reset process!If the Redmi Note 9 battery runs out during formatting, the phone may turn into a "brick" and require flashing through the computer. Charge the device to at least 60% before starting.
Prevention and optimization of the system
To avoid wondering how to clean your phone every two weeks, it's worth introducing simple usage habits: Regular maintenance takes less time than dealing with the effects of a full memory.
Turn on automatic cleaning in the Security app. In the settings of this app, you can set a schedule, for example, every 3 days, and the phone will delete temporary files in the background.
Also set up automatic cleaning in messengers, Telegram and WhatsApp can set a limit on the shelf life of media files, for example, set up automatic deletion of videos older than 3 days or months.
💡
Regular reboot of the smartphone (at least once a week) helps to reset the accumulated system processes and clear the memory, which has a positive effect on the speed of work.
Use cloud storage. Set up a gallery sync with Google Photos or Mi Cloud with Free Space, which automatically removes photos from your phone that are already securely stored in the cloud.