Smartphones of the Redmi line from Xiaomi are deservedly popular due to the excellent price-quality ratio, but owners of the Redmi 9 model often face a lack of built-in storage. The MIUI operating system, although it offers many convenient functions, over time, overgrows with temporary files, application cache and system debris, which significantly slows down the device. The user may notice that the phone begins to open programs longer, slow down when switching between tasks or completely stop receiving new messages due to a crowded drive.
Timely memory cleaning is critical to maintaining the stability of the gadget and extending the life of its battery, as a full disk makes the processor work with increased load. In this article, we will discuss in detail all the available ways to free up space, from using embedded tools of the system to manually deleting hidden files and transferring data to an external medium. You will learn to distinguish important system files from safe debris and can return your device to its previous speed without having to buy a new smartphone.
Regular file system maintenance avoids critical errors such as a cyclical reboot or the inability to update the operating system. Many users ignore notifications of a lack of space until the last moment, which can lead to the loss of important data in a sudden crash. Let's look at the main reasons why memory fills up so quickly, and how to combat this phenomenon.
Analysis of storage occupancy through settings
Before you start taking drastic measures, you need to determine exactly what exactly takes up precious gigabytes on your Redmi 9. The Android operating system in the shell of MIUI provides a built-in tool for detailed disk space analysis that allows you to visualize the distribution of files. To access this information, go to the Settings → Memory menu, where the system automatically scans the drive and gives a detailed report.
In the window that opens, you'll see a color diagram that shows different shades of data categories: apps, images, videos, audio files, documents and system files. The largest volume is usually occupied by messengers like Telegram or WhatsApp, which store all the media files received, as well as social networking and streaming services cache. Understanding the structure of the occupied space will help you make an informed decision about what can be removed without compromising the functionality of the device.
Note the “Other” section, which often raises questions from users, which includes files that the system cannot uniquely classify: it can be remnants of deleted applications, error logs, temporary update files or game data. If this category exceeds 5-10 GB, a deeper cleaning is required using file managers or specialized software.
⚠️ Note: Do not delete files from system folders that you do not know the purpose of, even if they take up a lot of space. MIUI or loss of settings.
Use of the built-in "Security" application
The easiest and safest way to free up space is to use the pre-installed Security app that is available on every Xiaomi smartphone, which is designed specifically to optimize the operation of devices running MIUI and is able to find hidden debris that is not visible when you normally browse folders. Launch the application and click on the “Clean up” button, after which the system will scan and suggest that you delete temporary files, uninstall package residues and advertising debris.
Deep Clean, inside the same app, allows you to find large files, rarely used apps and duplicate photos. The algorithm analyzes the contents of memory and groupes files by type, suggesting that you delete, for example, all screenshots older than a month or videos larger than 100 MB. This is a great way to quickly find heavyweights, which you may not even know existed.
In addition, the Memory section of the Security app allows you to set up automatic cache cleanup. Although you don't need to rely on automation completely, running this feature regularly helps keep the system in good shape. Once you've cleaned it, it's recommended that you restart the device so that the changes take effect and the file system is re-indexed.
☑️ Quick Cleaning Plan through Security
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For a more efficient cleaner, close all running applications before running the scan, allowing the system to gain full access to files that can be blocked by active processes.
Clearing the cache and data messengers
Messengers are the main memory consumers on modern smartphones, and Redmi 9 is no exception. Apps like WhatsApp, Viber and especially Telegram store copies of all photos, videos and documents sent and received in local memory, even if you have already viewed them on other devices. Over time, folders with media files of these applications can grow to tens of gigabytes, quietly eating up free space.
To clear the cache of a particular application, go to Settings → Applications → All applications, find the right messenger in the list and select Storage. Here you will see two buttons: Clear cache and Clear everything (or Delete data) Clearing the cache is a safe procedure that will delete temporary files, but save your correspondence and logins. However, the Clean All button will reset the application to the state immediately after installation, removing all correspondence history and authorization, so use it only as a last resort.
Telegram itself has a built-in automatic cache cleanup feature that you must activate. Go to Settings → Data and memory → Memory Use and set a cache limit, such as 500 MB or 1 GB, and enable autodelete media files in 3 days or a week, which will prevent uncontrolled growth of application folders in the future.
Why is the messenger cache so big?
Removal of duplicates and large files
During active use of the smartphone, duplicate photos, downloaded APK installation files and forgotten high-resolution videos are often accumulated in memory. Manually search for such files across all folders is long and inconvenient, so it is better to use a built-in sorter. In the standard MIUI Explorer (Files Application), there is a convenient sorting by size that instantly shows the largest objects on the disk.
Note the Download folder, where browsers and messengers default to save all downloaded documents, and often you can find old presentations, game installers, or other downloads. PDF-files that have already lost their relevance. DCIM →.thumbnails, where the thumbnails of the gallery are stored - this file can weigh several gigabytes and can be safely deleted, it recreated automatically.
You can use third-party apps from Google Play to find duplicate photos, as standard Xiaomi functionality does not always see identical images with different file names. Deleting repetitive images taken in batch mode or saved from different sources can instantly free up several gigabytes.
| File type | Typical size | Where to find | Security of removal |
|---|---|---|---|
| Cash app. | 100MB - 2GB | Settings → Applications | Safe (data will be retained) |
| File.thumbnails | 500MB - 5GB | DCIM/.thumbnails | Safe (recovered) |
| APK installers | 50MB - 2GB | Download folder | Safe (if the app is worth it) |
| Error logs (Logs) | 100MB - 1GB | System folders | Safe. |
Transfer applications and files to SD-map
Xiaomi Redmi 9 is equipped with a microSD card slot, which is a great solution to the problem of lack of built-in storage. Transferring media files (photos, videos, music) to an external card is the most effective way to free up internal memory for the system to work and install new applications. To do this, insert the card into the slot, wait for its recognition and select formatting when you request the system.
Once you've prepared the map, you can set up automatic saving of new photos and videos right on it. Go to the Camera app, click three bars in the corner of the screen to open the settings, and find "Save on" SD-A similar setup can be found in music players, voice recorders and some file managers, which will allow internal memory to remain free for cache system processes.
With the transfer of the applications themselves, the situation is more complicated: modern versions of Android do not always allow you to move programs to an external map to ensure speed and data security. MIUI There is a function "Memory Extension" that uses a part of the SD-cards are like virtual RAM, but to free up space, it is better to simply transfer heavy files there through the file manager, highlighting them and selecting "Move them".
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Using a high-quality memory card of the U1 or U3 speed class is critical for the smartphone, otherwise the interface may start to slow down when accessing files on an external medium.
⚠️ Attention: Before extraction SD-cards always perform the unmounting procedure through the Settings menu → Memory. → SD-map → Extract. Abrupt removal of a working card can damage the file table and cause data loss.
Radical methods: Reset to factory settings
If none of the above methods yielded the desired result and the memory continues to fill up with incomprehensible files, it is possible that the system has accumulated critical file spreadsheet errors or malware. In this case, the most effective solution will be a complete reset of the device to the factory settings (Hard Reset), which procedure will return the smartphone to the state in which it was at the time of purchase, completely clearing the user partition of memory.
Before you start, make sure to back up all your important data, because the reset process will remove all your contacts, photos, apps and settings, and you can do this through Mi Cloud, Google Account, or simply copy the files to your computer, and once you reset, you'll get a clean, garbage-free system that often creatively transforms your device's performance.
To perform the reset, go to Settings → About Phone → Settings Reset → Erase all data. The system will ask you to enter the unlock password and confirm the action. The process will take 5 to 15 minutes, after which the phone will restart and prompt you to go through the initial setup, this is a guaranteed way to get rid of any software errors affecting memory.