Where does memory go on Xiaomi smartphones: a full analysis + instructions for cleaning

Have you noticed that your Xiaomi memory melts like snow in the spring, even though you barely installed anything? Or did your phone suddenly start to issue a warning, "Not enough memory" when it was still 5GB free yesterday? This problem is familiar to most owners of Redmi, POCO and Mi smartphones — and it's not always related to your actions. It's about the features of MIUI firmware, hidden processes and "smart" algorithms that automatically reserve up to 20% of memory for system needs, even if you didn't ask for it.

In this article, we will not just list trivial tips like “delete unnecessary photos,” but we will explore 7 real reasons why memory goes nowhere, including little-known MIUI chips that are not even documented in the official certificate, and we will also give step-by-step instructions on how to regain control of the storage — from manually cleaning the hidden cache to turning off “vulnerable” functions that you did not even know about.

1. /data system partition and why MIUI steals memory

The main reason for the memory shortage on Xiaomi is the firmware architecture. Unlike pure Android, MIUI actively uses the /data partition for storage:

• 📦 Duplicate APK-files (yes, the system saves copies of installed applications "just in case»)
• 🔄 Temporary update files (even if you have disabled auto-update, MIUI downloads packages in the background)
• 📊 Logs and dumps (debugging files that take up to 1-2 GB and are never automatically cleared)

But the worst part is dynamic memory backup. Starting with MIUI 12, the system automatically freezes some of the free space for future needs. For example, if you have 8 GB free, MIUI can lock 1-1.5 GB in reserve, and you can not use them. You can check this through Settings → About Phone → Memory → System memory – there you will see the line “Reserved by system”.

Another memory eater is the F2FS file system that Xiaomi uses on most models, which is faster but less efficient in terms of storing small files, for example, 1,000 1MB photos will take up 1.2-1.3GB instead of 1GB because of the distribution of blocks.

2 App cache: why 5GB of 'garbage' is the norm for MIUI

Cache is a temporary file that apps create to speed up work. In pure Android, cache usually takes 100-300 MB. On Xiaomi, this value can go up to 5-7 GB, and here's why:

• 🎵 Music services (Mi Music, Spotify) cache tracks even in offline mode, if you have ever enabled this option.
• 📺 Video players (Mi Video, YouTube) save thumbnails and pre-load buffers.
• 🗺️ Maps (Google Maps, Yandex.Maps) download offline maps of regions you haven’t even opened.
• 🤖 AI services (Mi) AI, Google Assistant: Stores voice and image recognition models.

The most insidious thing is that the cache doesn’t clear automatically when there’s a memory shortage, as Android does on other smartphones, and some apps (like Facebook or TikTok) recover the cache immediately after cleaning, unless background activity is turned off.

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To see the actual cache size, go to Settings → Applications → Application Management → Size Sort. There you will find apps with cache over 500MB – they should be cleaned first.

But there is a caveat: do not clear the cache of system applications (for example, com.miui.home or com.android.systemui). This can cause MIUI malfunctions, up to the launcher's "outputs." Better use the built-in Settings → Memory → Cleanup, which deletes only secure temporary files.

3. Hidden MIUI folders: Where to look for gigabytes of "invisible" files

MIUI creates a few hidden folders that don't appear in the standard file manager, but take up space.

To see these folders, you’ll need a file manager that supports root or hidden files (like Solid Explorer or FX File Explorer).The alternative is to connect the phone to your PC and enable the display of hidden files in Explorer.

Pay special attention to the Android/data folder, which stores app data that can be deleted without affecting the operation of programs, such as folders of games that you have not run in a long time, or the cache of messengers (Telegram, WhatsApp), where gigabytes of unnecessary media files can lie.

4. Automatic backups and cloud synchronization

Xiaomi is actively promoting its cloud services, and many features are enabled by default.

• ☁️ Mi Cloud automatically uploads photos, contacts and notes, but duplicates them locally in the folder. MIUI/Backup.
• 🔄 Backup MIUI Creates images of the system once a week (files weigh 500 MB-1 GB each).
• 📱 Sync with other devices (if you have a Xiaomi laptop or smartwatch) copies files in the background.

Check what exactly is synchronized, you can in Settings → Xiaomi Account → Mi Cloud. Pay attention to the items “Gallery”, “Notes” – they are often enabled by default and duplicate data.

Open Settings → Xiaomi Account → Mi Cloud

Turn off automatic uploading of photos and videos

Disable backup for unnecessary applications

Remove old backups to Settings → Additional → Backup and Reset

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Another trap is automatic backup before updating MIUI. Before each major firmware, the system creates a backup of current settings that can weigh up to 2 GB. These files are stored in /MIUI/Backup/Update and are never deleted automatically.

5. Pre-installed applications and their “shadow” updates

Xiaomi is famous for its abundance of pre-installed apps, many of which cannot be removed by standard means, but the problem is not with them, but with how they are updated:

• 🔄 Background Updates: Even if you have disabled Auto Update in the Play Market, system apps (Mi Browser, Mi Music, GetApps) are updated via the Play Market. MIUI Updater.
• 📦 Duplicate APK: When you update, the system does not replace the application file, but saves the new version next to the old one (sometimes both versions take place simultaneously).
• 🔍 Hidden Services: Apps like Mi Security or Mi Share run background processes that create logs and cache.

To see the full list of system applications, use the command in ADB:

adb shell pm list packages -s

This will show all the apps that can't be removed without root rights, but some of them can be disabled:

1. Go to Settings → Applications → Application Management.
2. Click on the three dots in the top right corner and select "Show Systems."
3. Find unnecessary apps (e.g. Mi Pay, Mi Credit, Mi Video) and click Disable.

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Disabling system applications releases not only memory, but also RAM, which speeds up the phone, but do not turn off services called com.android. or com.miui. - this can lead to unstable system operation.

If you’re willing to go further, you can uninstall some rootless system apps using ADB. For example, to uninstall Mi Browser, do:

adb shell pm uninstall --user 0 com.android.browser

6. File system errors and memory fragmentation

Over time, the file system on Xiaomi (especially on models with eMMCs, such as the Redmi 9A or POCO M3) begins to fragment, which means that files are broken into small pieces scattered throughout the disk and take up more space than they should.

Signs of fragmentation:

• 🐢 Phone brakes when opening gallery or file manager.
• 📉 Free space “disappears” after the reboot (for example, it was 3 GB, became 1 GB for no apparent reason).
• 🔄 Copying files takes much longer than before.

The problem can be solved in two ways:

1. Reset to factory settings (completely cleans and reassembles the file system).
2. Use defragmentation utilities (e.g. SD Maid or Files by Google with cleaning function).

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Before reset, back up your important data! After reset, all files in your internal memory will be deleted. Use Settings → Additional → Backup and Reset → Local Backup.

Another common error is corrupted files that take up space but don't show up in the manager, and you can check for them through ADB:

adb shell ls -la /storage/emulated/0/ | grep "?"

If the team returns files with the “?” character in the title, they can be manually deleted.

7 Viruses, Mining and Hidden Processes

Although MIUI has built-in protection (Mi Security), some malware can bypass it, and Xiaomi is especially popular with:

• 🕵️ Spyware that steals data and sends it to the server (you can see the unexpected increase in traffic).
• ⛏️ Cryptocurrency miners who use phone resources to mine Monero or Bitcoin.
• 📱 Fake updates that masquerade as system notifications and install unnecessary programs.

You can check your phone for viruses by:

1. Mi Security (built-in scanner in Settings → Security).
2. Malwarebytes or Kaspersky Mobile (download only from the official Play Market).
3. Manually check in Settings → Applications for suspicious programs (for example, with names like com.system.update or android.service.secure).

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If you notice that the phone is warming for no reason or discharges quickly, even when not in use, this is a sure sign of hidden mining or a virus. Check the list of running processes in Settings → About the phone → System Status → Running processes.

One of the most insidious viruses for Xiaomi is xHelper, which is installed in the system partition and restored after removal, and the only way to get rid of it is to completely reset your settings or flash it through Fastboot.

FAQ: Frequent questions about memory on Xiaomi