Your Xiaomi Mi 9 is slowing down, apps are suddenly shutting down, and the system is giving notifications about memory shortages? The problem is familiar to many owners of this flagship of 2019. Even with 64 or 128 GB of internal memory, garbage accumulates over time: app cache, duplicate photos, residual files after updates and unnecessary data from MIUI. In this article, we will analyze 7 proven ways to clean up memory — from simple to radical, and also tell you how to avoid repeated clogging.
The Mi 9 feature is that there is no memory card slot, so every megabyte counts. Fortunately, the system offers built-in optimization tools, but they don't always cope with deep cleaning. We tested all methods on current versions of MIUI 14 and Android 12 so you can choose the most efficient option without risking damaging data.
Before you start, check how much memory is occupied: go to Settings → About Phone → Memory. If less than 10% is free, it’s time to act! And if the phone gives an error “Insufficient memory” when installing applications, skip the first steps and immediately proceed to deep cleaning.
Basic methods: cache, garbage and temporary files
Start with the safest ways that don’t affect personal data. In Mi 9, app cache and system debris can take up to 5-8 GB – especially if you are actively using social networks, instant messengers and streaming services.
To clear the cache of all applications at once:
- Open Settings → Applications → Application Management.
- Click on the three dots in the top right corner and select Clear Cache.
- Confirm the action – the system will delete temporary files in a few seconds.
To clean the garbage manually:
- 📁 Download folder: here you can collect downloaded files from your browser, messengers and email. PDF, APK archives.
- 🗑️ Recycle bin: in the Mi 9 gallery, deleted photos and videos are stored for 30 days. → Basket → Clean up.
- 🔄 Residual files: after uninstallation of applications, folders remain in the /Android/data/. Remove them through the file manager (e.g., Mi File Manager).
⚠️ Note: Do not delete folders called com.xiaomi.* or android - this may disrupt the system.
2. built-in MIUI tools for optimization
MIUI offers a few utilities for automatic cleaning, but they often don't work well. Let's figure out how to make them work to the fullest.
The first tool is memory optimization:
- Go to Settings → Special features → Memory optimization.
- Enable the Auto Clean option and set a schedule (we recommend daily at 3:00).
- Click Clean Now to remove background processes and free RAM.
The second is Security (Security app):
- 🧹 Acceleration: Remove unnecessary processes and cache (available on the home screen of the app).
- 🗃️ Deep Cleanup: Analyzes large files, duplicates and rarely used applications. Run the scan and manually select which to delete.
- 🔍 Virus check: some malware creates hidden files that take up space. Do a check even if the antivirus is disabled.
| MIUI instrument | What cleanses | Efficiency |
|---|---|---|
| Optimizing memory | Background processes, RAM cache | Low (temporary effect) |
| Safety → Acceleration | App cache, junk files | Medium (1-3 GB) |
| Security → Deep cleaning | Duplicates, large files, rare applications | High (3-10GB) |
| Storage → Memory Analysis | Visualization of occupied space | Informational (not cleansing) |
If there is still little free space after using these tools, proceed to the following methods.
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Include Memory Compression in Settings → Additional → Lab (not available on all versions of MIUI) to reduce the amount of system processes you use by 10 to 15 percent.
3. Application Management: What Can Be Removed Without Risk
Many Mi 9 users install dozens of apps, but only a few, and even unused programs take up space: their data, cache, and updates. Here's how to safely dispose of them:
List of applications that can be removed without consequences:
- 🎮 Games you do not play (for example, games you do not play, PUBG Mobile, Call of Duty – they weigh 1-2 GB).
- 📱 Duplicate applications (for example, two browsers or two messengers).
- 🛒 Apps of stores you do not use (AliExpress, Wildberries, etc.).
- 📺 Streaming services if you only watch videos on YouTube (KION, Okko, IVI).
- 📊 Fitness or health apps if you don’t use a fitness bracelet.
To remove system applications (e.g. Mi Music, Mi Video, Browser), root or other rights will be required. ADB-Without them, you can only turn off their updates and clean up the data:
- Go to Settings → Applications → Application Management.
- Select an unnecessary system application (such as Mi Pay).
- Click Disable (if available) or Clear Data.
- In the Warehouse section, turn off Auto Update.
⚠️ Note: Do not remove or disable system applications called com.android., com.xiaomi.finddevice or com.miui. – this can cause malfunctions in the phone.
Check the size of the application in Settings → Applications
Make sure there are no important data (e.g. saves in games)
Turn off auto-update in Google Play
Backup (if the application contains important information)
Remove the cache before uninstallation-->
4. Deep Cleanup: Hidden Files and Technical Folders
If the basic methods didn’t work, it’s time to dig deeper. The Xiaomi Mi 9 has hidden folders and files that aren’t visible in a standard file manager, but take up gigabytes of memory. To remove them, you’ll need Root Explorer or FX File Manager with hidden file mode enabled.
Where to look for garbage:
- 📂 /data/log/ — System log files (you can delete everything except the current logs).
- 📂 /data/tombstones/ — Error dumps (delete all files with the.tombstone extension).
- 📂 /data/system/package_cache/ — cache of installed packages (remove the contents).
- 📂 /sdcard/Android/obb/ — Game files (e.g. Genshin Impact or Honkai: Star Rail) can take up to 10 GB).
- 📂 /sdcard/MIUI/ — Temporary theme and wallpaper files (remove theme and wallpaper folders if you don’t use custom themes).
To clean up the cache of Google Play Services (often takes 1-2 GB):
- Go to Settings → Applications → All applications.
- Find Google Play Services and click Storage.
- Select Clear Cache and Control Space → Clear all data.
If you are using Google Photos for backup, check the /sdcard/DCIM/.thumbnails folder – it stores thumbnails of photos that can be safely deleted.
What to do if you do not have enough permissions to delete files?
5. Transfer data to the cloud and external media
If you don’t want to delete anything, transfer your files to the cloud or external drive. Xiaomi Mi 9 does not support memory cards, but you can use:
- ☁️ Cloud storage: Google Drive (15GB free). Mi Cloud (5GB free, integrated into the MIUI). Yandex Disk (10GB free).
- 💾 External drives: USB-flash-drive OTG-Adapter (formats supported) FAT32, exFAT) Portable SSD-storage device (for large amounts of data).
- 📱 Other devices: Transfer files to PC over Wi-Fi via Mi Drop or LocalSend. Using the second phone as a drive (via Wi-Fi) FTP-server).
To automate backup:
- Open the Gallery and go to Settings → Backup.
- Enable Autoboot in Mi Cloud for photos and videos.
- In Google Photos, activate Backup and Sync.
⚠️ Note: When transferring files to an external drive through OTG Do not remove the flash drive without safely shutting down (Notifications) → Shut down. USB-This can cause data damage.
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Moving files to the cloud doesn’t free up memory on your phone unless you delete local copies. After downloading, check the DCIM and Download folders and clear them.
Extreme measures: reset to factory settings
If all the previous methods didn't work, and the phone is still slowing down, you're left resetting to factory settings, which is a radical way to delete all the data, including apps, photos, contacts and settings.
- 🔄 Make a backup copy through Settings → Additionally. → Backup and reset → Local backup.
- ☁️ Sync contacts, notes and passwords with your Mi Account or Google.
- 📎 Save important files to your PC or cloud.
- 📱 Remember or take a picture of your network settings (Wi-Fi passwords, APN mobile-internet).
Resetting instructions:
- Go to Settings → About the phone → Reset settings.
- Select to erase all data (reset to factory).
- Enter the password from the Mi Account (if linked).
- Confirm the action and wait for the reboot (it will take 5-10 minutes).
Once reset, the phone will be like new. Don't restore the backup right away -- first check if the reset solves the memory problem. If so, recover the data selectively, avoiding unnecessary apps.
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If the phone still brakes after reset, check the health of the drive using the AIDA64 app (Storeroom → Memory Status) may need to replace the internal drive.
7.How to prevent future memory clogging
To avoid having to clean every few months, follow these rules:
- 📱 Remove unused applications immediately after installation if they are not needed.
- 📷 Optimize your photos and videos: In the Gallery, enable Storage Optimization (saves compressed versions). Use Google Photos in High Quality Mode (unoriginal, but saves space).
- 🔄 Clean the cache regularly: Install SD Maid or Files by Google for automatic cleaning.Enable weekly cleaning in Security → Autocleaning.
- 🚫 Avoid junk apps: Don't install memory cleaners from unknown developers - they often become a source of garbage themselves.
- 📥 Control downloads: Remove the habit of saving everything from messengers (on Telegram and WhatsApp, set up automatic media removal). → Annexes → Permits → Storage to restrict applications access to memory.
If you install new apps frequently, use Island or Shelter, which isolates test application data from the main system.