How to completely clean the Xiaomi Redmi 9 phone: from cache to reset to factory settings

Why Redmi 9 is slowing down and how to fix it

Xiaomi Redmi 9 with its 4GB of RAM and 64/128GB of internal storage seems quite powerful, but over time even it begins to “suffocate”: applications open for a long time, the system hangs, and the free space melts before your eyes, the reason lies not in the “weak hardware”, but in the accumulated digital garbage — the cache of applications, the remains of deleted files, duplicate photos and unoptimized settings.

Cleaning your phone isn't just about deleting a few files, it's a set of measures that includes working with the system cache, analyzing the space occupied, removing digital corpses (remnants of uninstalled software) and even resetting to factory status in critical cases. In this article, we'll look at 7 proven ways to bring your Redmi 9 back to its previous speed, from basic to radical.

It’s important to understand that on Redmi 9 with MIUI 12 and later, the built-in Cleanup feature only removes surface debris, leaving up to 30% of the “invisible” files that continue to occupy space, so you’ll have to use both manual methods and third-party tools.

Method 1: Integrated MIUI cleaning – fast but inefficient

So, to start with, the simplest tool is the regular MIUI tool, which is available in two clicks, but unfortunately, only clears the tip of the iceberg, but it's a good first step before a deep cleaning.

How to start:

1. Open the settings → About the phone → Memory.
2. Slip the Clean button (usually displayed at the bottom of the screen).
3. Wait for the analysis (taken 1-2 minutes) and confirm the removal.

What the built-in cleaning removes:

• 🗑️ Temporary application files (cache)
• 📁 Empty folders and thumbnails
• 🔍 Remains from the remote APK (not always)

What it doesn't delete:

• 🚫 System cache (/cache and /data/dalvik-cache)
• 🚫 Duplicate photos and videos (for example, from the DCIM/.thumbnails)
• 🚫 System and kernel logs (can weigh up to 500MB)

⚠️ Warning: If after cleaning, the Memory section still shows 80-90% of storage occupied, but you don't see large files, the problem is hidden system data.

Method 2: Manually cleansing the application cache

App cache is a black hole on Redmi 9. For example, Facebook or Instagram can accumulate up to 1-2 GB of cache in a few months, and unlike built-in cleaning, the manual method allows you to control what is deleted.

Instructions:

1. Go to Settings → Applications → Application Management.
2. Select the application (start with the most “heavy” – social networks, instant messengers, games).
3. Slip the vault. → Clear the cache.
4. For complete cleaning, click Clear Data (⚠️ This will reset the application settings!).

Top.-5 «cache-eaters on Redmi 9:

⚠️ Note: Do not clear Google Play Services, Android System and MIUI Core – This Can Lead to a Cyclical Phone Reboot.

Backup of important data

Close all background applications

Connect your phone to charge (if charge < 30%)

Do not interrupt the cleaning process-->

Method 3: Delete unnecessary files through Explorer

Redmi 9 has hidden folders that take up gigabytes of memory but remain invisible to the user, such as the MIUI/Backup folder can weigh up to 3 GB due to old backups, and the DCIM/.thumbnails folder can store thumbnails of deleted photos.

How to find and remove garbage:

1. Open Explorer (standard MIUI application).
2. Enable the display of hidden files: ⋮ → Settings → Show hidden files.
3. Go to the root folder of the storage and check the following directories:

• 📂 MIUI/Backup — Old backups (remove everything except the last one)
• 📂 DCIM/.thumbnails — Miniatures (can be removed completely)
• 📂 Download – downloads (sort by size)
• 📂 Android/data — Remnants of Remote Games (Folders with the Name of Games)

Pay special attention to the Android/obb folder – additional game files are stored here (for example, PUBG or Call of Duty Mobile can take 1-2 GB even after the game is deleted).

Method 4: Cleaning the system cache with Recovery Mode

The system cache (/cache) and Dalvik cache (/data/dalvik-cache) are not cleaned by standard methods, but their accumulation can lead to slowdowns and even accidental reboots.

Step-by-step:

1. Turn off the phone.
2. Press the Power + Volume buttons up for 10 seconds until the MI logo appears.
3. In the Recovery menu, select the language (English / Whale) and tap Wipe & Reset.
4. Select Wipe Cache (not to be confused with Wipe All Data!).
5. Confirm the action and wait until the completion (1-2 minutes).
6. Restart the phone (Reboot).

This method is secure and does not delete user data, but requires caution:

• ✅ You can do it every 2-3 months for prevention.
• ❌ Not to be confused with Wipe All Data – it’s a complete reset!
• ⚠️ If the phone is loaded for a long time (5-10 minutes) after cleaning, this is normal.

💡

If the phone still brakes after cleaning the cache in Recovery, check the processor boot in Settings → About Phone → System Status. If the CPU is loaded 80-100% in idle, a virus or firmware failure is possible.

Method 5: Use of third-party cleaners (with caution!)

Apps like CCleaner, SD Maid, or Files by Google promise “magic” cleanups, but in practice often delete files or display false warnings.

Top.-3 Proven utilities for Redmi 9:

How to use it safely:

• 🛡️ Before cleaning, create a backup copy (for example, through Settings). → Additionally. → Backup).
• 🔍 Don’t settle for registry or autoload “optimization” – it’s a marketing trick.
• 🚫 Avoid apps with names like “Super Cleaner” or “Phone Booster” – they often contain adware.

⚠️ Attention: Redmi 9s MIUI 13+ Some cleaners (such as Clean Master) can block system processes, causing an error «MIUI stop».

Method 6: Reset to factory settings (radical method)

If the phone is unbearably slow and the memory is full, there's no telling what, the last chance to bring it back to life.

• 📱 All installed applications and their data
• 📸 Photos, videos, music (if not) SD-map)
• 🔑 Accounts, passwords, Wi-Fi settings
• 📋 Messages, contacts, call log

How to reset:

1. Create a backup copy (required!):
2. Go to Settings → About the phone → Reset settings.
3. Choose to erase all data and confirm.
4. Wait for the finish (5-10 minutes) and set the phone up as new.

What to do after the discharge:

• 🔄 Recover data from the backup (but not all – choose only the right one!).
• 🚫 Don’t install all apps at once – add them gradually while watching performance.
• 🔧 Turn off the autoload of unnecessary programs in Settings → Annexes → Auto-start.

💡

Factory reset is the only way to get rid of viruses in system files and irreparable MIUI errors, but use it only as a last resort.

Method 7: Optimizing Memory for Prevention

To avoid bringing your phone to the state of “cluttered with garbage”, follow the simple rules:

• 📅 Once a month, clean the application cache (method 2).
• 📷 Transfer photos and videos to SD-Map or cloud (Google Photos, Mi Cloud).
• 🎮 Remove games through Settings → Applications, not just clicking “Delete” – this will clean all residual files.
• 🔄 Update. MIUI Up to the latest version – in the new firmware optimized work with memory.

It is also useful to disable unnecessary system processes:

1. Go to Settings → Applications → Application Management → System.
2. Find MIUI Daemon, Analytics, MSA (if you don’t use Xiaomi services).
3. Put it on or off.

These measures will reduce the load on the processor and prevent fragmentation of memory, which often causes brakes.

FAQ: Frequent questions about cleaning up Redmi 9