How to clean Xiaomi Redmi Note 9 Pro: from cache to complete reset

Your Xiaomi Redmi Note 9 Pro has become slow, quickly discharge or give out “not enough memory” errors? The reason most often lies in clogged cache, unnecessary files and background debris that accumulates over time. Even a powerful Snapdragon 720G processor and 6 GB of RAM will not save if the system is cluttered.

In this article, 7 proven ways to clean your smartphone, from basic (cache removal) to radical (full reset to factory settings), we will discuss how to make room without losing important data, which tools to use and which to abandon, and also unique nuances for the Redmi Note 9 Pro model that do not work on other Xiaomi smartphones.

1.Diagnostics: What exactly is cluttering your Redmi Note 9 Pro?

Before you start cleaning, you need to understand what exactly is taking up memory. The Redmi Note 9 Pro has built-in analysis tools, but they don't always show the full picture.

• 📊 Built-in Analyzer: Go to Settings → The phone. → Memory. Here you will see the distribution of memory by category (applications, media, system files). Note the "Other" section if it occupies >10 GB, this is a signal of accumulation of garbage.
• 🔍 Hidden files: Many applications (such as messengers) store data in folders.thumbnails,.cache or Android/data, Not visible without a root file manager.
• 📱 Background Processes: Open Settings → Annexes → If there are more than 20 active processes, the system is overloaded.

The Redmi Note 9 Pro has a feature: the system partition /system takes ~12 GB, and it can't be cleaned without root rights. But often users confuse it with user data. If you see in memory analysis that "System" takes up a lot of space, that's OK, but "Cache" or "Other" >5 GB is a reason to clean.

⚠️ Note: Do not manually delete files from the folder /system or /vendor — This will lead to the inoperability of the smartphone and require flashing.

2.Cleaning App Cache: A Quick Way to Free 1-3GB

App cache is a temporary file that speeds up programs but eventually turns into junk. On the Redmi Note 9 Pro, the cache can take up to 5-7 GB if never cleaned. Here's how to do it right:

Method 1: Clearing the cache for individual applications

1. Go to Settings → Applications → Application Management.
2. Select an app (such as Facebook or YouTube).
3. Press Warehouse. → Clear the cache.

Method 2: Mass cleaning of the cache

For this:

1. Open Settings → Memory → Cleaning.
2. Click Clear cache (the system will show how much space will be freed).
3. Confirm the action.

There's a bug on the Redmi Note 9 Pro: After mass cache clearing, some apps (like the Google Play Store) may freeze when you first run. That's okay - just restart your phone.

Delete the cache of messengers (Telegram, WhatsApp)

Clean up the social media cache (Facebook, Instagram)

Delete the browser cache (Chrome, Mi Browser)

Clear the game cache (PUBG, Genshin Impact)-->

Method 3: Automatic cleaning (for lazy people)

Enable the Auto Clean function:

1. Settings → Memory → Autocleaning.
2. Activate the switch and select a frequency (e.g., "Every Week").

⚠️ Note: Do not clear the cache for applications that use offline maps (such as Google Maps or Yandex.Navigator) and this will delete the downloaded data and have to download it again.

3. Deletion of unnecessary files and “digital garbage”

Even if you clean the cache regularly, the Redmi Note 9 Pro accumulates over time:

• 📁 Duplicate photos/video (for example, after editing in Google Photos).
• 🎵 Unused audio files (downloads from messengers, voice messages).
• 📄 Outdated. APK-Files (remain after installing apps not from the Play Market).
• 🗑️.trash and Recycle Bin folders (hidden baskets of file managers).

To find and remove garbage, use:

The Redmi Note 9 Pro has a hidden /MIUI/ss folder that stores screenshots taken by the system (e.g., when errors occur) that can weigh up to 500MB.

1. Open Mi File Manager.
2. Enable the display of hidden folders (⋮ → Settings → Show hidden files).
3. Go to /storage/emulated/0/MIUI/ss and delete any unnecessary files.

💡

Before mass deletion of files, back up important data to Mi Cloud or PC. Redmi Note 9 Pro has a built-in Settings feature → About Phone → Backup

4.Storage optimization: what can be removed without consequences

Many users are afraid to delete files for fear of breaking the system.In fact, on the Redmi Note 9 Pro, you can safely delete:

• 🎬 Video in resolution 4K (occupy ~400MB/min. Move them to your PC or cloud.
• 📷 Photo format RAW (weight 20-30 MB each. Convert to JPG.
• 🎮 Game data (cash) PUBG Mobile can weigh >2GB. Remove via Settings → Annexes → PUBG → Warehouse → Clear the data.
• 📥 Downloads from messengers. In Telegram, go to Settings → Data and memory → Warehouse → Clear the cache.

Here's what you can't delete:

• 🚫 Android folder (except for the obb subfolder for games).
• 🚫 Files with the.odex or.vdex extension.
• 🚫 folder MIUI (except MIUI/ss and MIUI/Gallery).

5.Reset to factory settings: when it really needs to

If all previous methods failed and the Redmi Note 9 Pro is still slowing down, the last option is a full reset.

• 📱 Applications and their settings.
• 📁 Photos, videos, music (if not on the list) SD-map).
• 🔑 Accounts and passwords (except those synced to Mi Account).
• 📱 System settings (wallpaper, sounds, network parameters).

How to do the reset correctly:

1. Save important data to your PC or cloud.
2. Go to Settings → About Phone → Resetting → Erase all data.
3. Enter your password (if installed) and confirm.
4. Wait for the reboot (it will take ~5-10 minutes).

On the Redmi Note 9 Pro, it can hang on the MI logo after a reset. It's OK to wait 10-15 minutes. If the phone doesn't turn on for longer than 20 minutes, try:

1. Press Power + Volume up for 10 seconds (forced reboot).
2. If it doesn’t help, try the Mi Flash Tool (instructions in the next section).

⚠️ Note: After resetting the Redmi Note 9 Pro may require you to enter the old password Google (FRP-If you don’t remember it, you’ll have to wait 72 hours to unlock it or use the official unlock tool from Xiaomi.

💡

Factory reset is a last resort, and 80 percent of the time, it's enough to clean the cache and delete unnecessary files.

6. Flashing: A Radical Method for Power Users

If the smartphone still doesn't work well after the reset, it could be a broken firmware, as the Redmi Note 9 Pro shows:

• 🔄 Self-involved reboots.
• 📵 Loss of network or Wi-Fi.
• 🔋 Quick battery discharge (even after battery replacement).
• 🛑 Hanging on the logo MI or Fastboot.

You'll need to flash it back:

• 🖥️ Windows computer.
• 🔌 Cable USB Type-C (original!).
• 📥 Firmware from the official Xiaomi website (choose the version for Redmi Note 9 Pro, joyeuse encoding).
• 🛠️ Mi Flash Tool Programming.

Step-by-step:

1. Download and install the Mi Flash Tool.
2. Unpack the firmware (file with.tgz extension) in a folder without Cyrillic characters.
3. Turn off the phone and press Power + Volume down to log into the Fastboot.
4. Connect your phone to your PC and start the Mi Flash Tool.
5. Press Select, select the folder with the firmware, then Refresh (you should see your device).
6. Select Clean All mode and press Flash.
7. Wait until it's finished (~5-10 minutes) and the phone will reboot automatically.

After flashing:

• 🔄 The phone will be as new as the new one, but all data will be deleted.
• 📱 When you first turn on, select the region "Russia" (even if you are not in Russia) to avoid problems with Google services.
• 🔄 Update your firmware to the latest version through Settings → Update of the PO.

7.Optimization after cleaning: how to avoid repeated cluttering

To prevent the Redmi Note 9 Pro from slowing down again in a month, follow these rules:

• 📵 Limit background activity: in Settings → Battery → Power management applications disable auto-start for unnecessary applications.
• 🔄 Set up automatic cleaning: turn on Settings → Memory. → Autocleaning (recommended interval - 1 time per week).
• 📥 Control Downloads: In Chrome or Mi Browser, turn off automatic file saving in Settings → Downloads. → Ask where to keep it.
• 🎮 Limit the game cache: in PUBG Mobile or Call of Duty reduce the quality of graphics in the settings.
• 📁 Use the Cloud: Set up an automatic photo upload to Google Photos or Mi Cloud and delete local copies.

Redmi Note 9 Pro has a hidden function “Light mode”, which reduces resource consumption:

1. Go to Settings → Special Opportunities → Light Mode.
2. Activate the switch.
3. Select applications that you want to simplify the interface for (this will reduce the load on the processor).

We also recommend:

• 🔋 Calibrate the battery: discharge the phone to 0%, then charge to 100% without interruptions.
• 📵 Disable Wi-Fi and Bluetooth search in the background: Settings → Connection → Wi-Fi/Bluetooth → Additionally. → Scanning is always available → Shut down.

💡

Regular cleaning of the cache and monitoring of background processes prolong the life of the battery by 15-20%.

FAQ: Frequent questions about cleaning Redmi Note 9 Pro