Why Xiaomi smartphones are always “lacking memory”: technical reasons and solutions

Did you buy the new Xiaomi Redmi Note 12 with its 128GB of storage claimed, but after first turning on, the system only shows 112GB? Or did your 256GB POCO X5 Pro suddenly start issuing space shortage notifications after a month of use, even though you have barely installed anything? This problem is familiar to millions of Xiaomi smartphone users - and it's not always related to the "gluttony" of modern apps.

In this article, we’ll look at 7 real reasons why Xiaomi devices (including Redmi, POCO, and Black Shark) have less memory than the box says — from the technical nuances of the file system to the hidden mechanisms of MIUI. And most importantly, you’ll learn how to free up to 20-30% of space without deleting important files using built-in tools and little-known tricks.

Spoiler: it's not just about cheating the manufacturer (albeit it's also about cheating), part of the memory is being eaten away by the Android architecture itself, another is being used to backup sections for updates, and a third is being consumed by system processes you don't even know about, and yes, we're going to tell you why even after you're completely reset to factory settings, you won't get all the lost gigabytes back.

1. Marketing vs Reality: Why 128GB ≠ 128GB

The first and most obvious reason is the difference in calculus systems: manufacturers (not just Xiaomi) list memory capacity in decimal gigabytes (where 1 GB = 1,000,000 bytes), and operating systems (Android, Windows, macOS) display it in binary gibbytes (where 1 GiB = 1,073,741,824 bytes).

• 📦 128GB on the box = ~119 GiB in your phone
• 📦 256GB on the box = ~238 GiB in a phone
• 📦 512GB on the box = ~476 GiB in your phone

This is not a “deception”, but a global practice, as do Samsung, Apple and other brands, but Xiaomi is exacerbated by the breakdown of memory into parts that are not written in the specifications, for example, in smartphones with UFS 2.2/3.1, some memory is reserved for:

• 🔄 Recovery section (recovery) — ~500MB
• 🔄 Partition of the bootloader (bootloader) — ~30-100 MB
• 🔄 Section for OTA-updates - before 2-3 GB (depending on the model)
• 🔄 Hidden section for logs (for diagnosis) — ~100-300 MB

In Xiaomi smartphones with MIUI 14+, the section for updates can take up to 5GB – this is “invisible” memory that can not be used for files or applications. For example, in Xiaomi 13 Pro of 256GB, the user can only access ~240GB “out of the box”.

MIUI and its “appetites”: hidden files and duplicates

The MIUI shell is one of the heaviest Android firmware, and even after a clean installation, it takes 12-18 GB (depending on version and model) to compare: the naked Android 13 without the shell weighs ~6-8 GB. Where does the rest go?

Especially “gluttonous” function “Smart cleaning” (Security) → Cleaner: It creates temporary files to analyze memory that are not always deleted automatically, such as scanning the system for viruses in a folder. /data/local/tmp You can still have files up to the size 1 GB.

Another thing MIUI does is automatically create duplicate photos when you edit in a gallery, and if you crop a photo or use a filter, the original is saved to a hidden folder called.thumbnails or.MIUI/editor, which accumulates up to 5-10 GB of junk over time.

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To find hidden duplicate folders, use a file manager (such as Mi File Manager) and enable the display of hidden files in the settings. Look for folders with a dot at the beginning of the title (such as.nomedia,.MIUI).

File system and its taxes: why F2FS and ext4 steal memory

Xiaomi smartphones use the F2FS (Flash-Friendly File System) or ext4 file system for the /data partition (where user files and applications are stored), which are optimized for flash memory, but have a feature: they reserve 5-10% of space for office needs:

• 📁 Journaling (for recovery after failures) – up to 1 GB
• 📁 Backup blocks (to replace "broken" cells) - up to 3-5% volume-wise
• 📁 Methodized (file information) – up to 1 GB of 128 GB of memory

For example, in the Redmi Note 11 Pro+ with 128GB of memory, the file system eats away at about 4-6GB that don’t show up in the settings.This is normal, but many users perceive this as “disappearance” of memory.

MIUI also uses data compression to save space, but it doesn’t always work efficiently, for example, application databases (like Telegram or WhatsApp) can take up 20-30% more space due to the compression features of SQLite.

4 MIUI updates: why they 'steal' memory forever

Every update MIUI (It's a minor partition that increases the size of the system partition, and the old files are not deleted, they stay in the folder. /cache/recovery or /data/ota_package in case of a rollback:

• 📲 One update MIUI 14 → MIUI 14.0.1 add ~300-500 MB of "undeletable" files.
• 📲 Major update (for example, with Android) 12 Android 13) may take up 1.5-2 GB.

Worst of all, even a factory reset doesn't clear these files. They stay in hidden partitions and keep taking up space, and as a result, after a year of use, a 128GB smartphone can only show 100-105GB of available space.

Another nuance: Xiaomi is using A/B-Update sections (two copies of the system between which the device switches) ensure stability, but require additional 2-4 GB of memory that is never given to the user.

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If you update your smartphone through Settings → Update MIUI, Always remove old service packs manually through the file manager (folder) downloaded_rom).

5.Cash and app junk: where gigabytes are hiding

Xiaomi apps are very active in using cache, which is a temporary file to speed things up, but many of them don't automatically clean the cache, and over time it grows to an incredible size.-5 «squash MIUI:

Social media is especially insidious: it stores copies of all videos, stories and even messages viewed in cache, for example, TikTok can “eat” up to 5 GB in a month of active use if you don’t manually clean the cache.

Another trap is the residual files of remote applications, which when you delete a program, its data often stays in /data/data or /sdcard/Android/data folders, for example, up to 1 GB of junk can remain in memory after PUBG Mobile is deleted.

🔹 Clear the cache only for specific applications (do not use "Clean everything")

🔹 Close the application before cleaning (otherwise the data will be restored)

🔹 For the gallery, use the built-in Settings function → Memory. → Clean the thumbnails.

🔹 Do not clear the cache of system applications (such as Settings or Phone)

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6.Viruses, advertising software and MIUI grey services

Not everyone knows, but MIUI has built-in services for data collection and advertising that run in the background.

• 🕵️ MSA (Miui System Ads – service for personalized advertising ~200-400 MB.
• 🕵️ Analytics – collects data on smartphone usage (~100-300 MB of dens).
• 🕵️ Xiaomi Cloud – Even if you don’t use the cloud, it caches data (~500MB).

These services cannot be removed without root rights, but they can be disabled:

1. Go to Settings → Memory → Applications.
2. Find the MSA (com.miui.systemAdSolution) and turn it off.
3. In Settings → Privacy → Special Permissions → Showing windows over others, disallow access for MSA and Analytics.

Xiaomi also has a lot of pre-installed ads (such as Mi Music or Mi Video) that download banners in the background, which can take up to 1 GB of traffic and memory per month.

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To block all ads in MIUI, install ADB AppControl and disable activity for com.miui.systemAdSolution and com.xiaomi.midrop.

7.How to recover lost memory: 5 working ways

Here are 5 proven methods that will help you free up 5 to 30 GB of memory in Xiaomi without deleting important files:

1. Transfer of applications to SD-Card (if supported): In Settings → Select the program and click Transfer to SD. It doesn’t work for all apps, but it saves you money. 5-10 GB.
2. Clean DCIM/.thumbnails folder: This folder stores thumbnails of all photos and videos and can be safely cleaned (miniatures will recover automatically).
3. Turn off automatic backup: Go to Settings → Accounts → Mi Cloud and turn off reservations for unnecessary data (such as notes or SMS).
4. Using Lite versions of apps: Replace Facebook with Facebook Lite, Messenger with Messenger Lite – this will save up to 1-2 GB.
5. Hand-cleaning the folder downloaded_rom: After updating MIUI Remove old firmware files from this folder (they can weigh up to a maximum of one). 3 GB).

If nothing works, try resetting to factory settings, but note: this will only return part of the memory (since system partitions will not be cleaned).

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The most effective way to free up memory is to use SD-card as internal storage (format as internal memory in settings) SD). But it will slow down the applications!

FAQ: Frequent questions about memory in Xiaomi

If you didn’t have enough answers to your question, check the official Xiaomi forums or contact the support with the model of the smartphone and the version of MIUI. Remember: memory in Xiaomi is always less than the stated one, but with the right approach, you can return up to 80-90% of the “lost” volume.