Owners of Xiaomi Redmi 9 smartphones often face a lack of built-in storage, especially given that the basic versions of the device offer only 32 or 64 gigabytes. The solution is to install a microSD memory card, however, after physical installation of the media, the system may not display files or require additional actions to work correctly. Integration of an external drive is not just inserting plastic into a slot, but a process that requires understanding the Android file system and the MIUI shell.
When properly configured, you can use the card as an extension of internal memory to which you can transfer heavy applications, or as a portable storage for media files. Errors in the initial configuration stage can cause the device to stop seeing files, photos or music. Below we will discuss in detail all the steps from physical installation to advanced formatting.
Physical Attitude and Primary Definition
The first step is always to physically fit the vehicle correctly. The Redmi 9 uses a combined tray, which means that you can install either two. SIM-card SIM It is important to make sure that the card is inserted on the correct side before clicking, as poor contact is often the cause of reading errors.
When the smartphone is turned on, the system automatically detects a new drive. Usually, a notification appears at the top of the screen suggesting that you configure the storage. If there is no notification, check the status in the notification curtain or go to the settings. Sometimes you need to reboot the device to initialize the memory controller.
⚠️ Warning: Never remove a memory card while the phone is on and writing or reading data is in progress.This can cause permanent damage to the file system and loss of information.
☑️ Pre-formatting verification
Type of use: Portable or Internal
When you first connect to Android, MIUI will prompt you to choose the mode of operation of the drive, which will depend on how your storage system will work. Portable storage mode leaves the card available for other devices (cameras, PCs) without formatting in a closed format, but limits the installation of applications.
Internal storage formats the card into a file system that only this particular phone can understand, encrypting the data for security, and extending the memory for applications and system processes, making the card an integral part of the smartphone, depending on your goals: if you want versatility, choose portable mode, if you don't have enough space for games, internal.
Step-by-step instructions for formatting the map
If the automatic offer doesn't appear, or you want to change the type of use, you need to format manually through the settings. This process completely cleans the media, so backing up the data is a must. MIUI The 12 or 13 that is relevant to the Redmi 9 is as follows:
1. Open the Settings menu and find the About Phone section or immediately go to Advanced Settings (depending on the firmware version).
2. Find the item "Storage" or "Memory".
3. In the list of available drives, select your SD-map (usually displayed as a SD Card).
4. Click on the three dots in the upper right corner or the Storage Settings button.
5. Select the Format option.
What happens when you format?
Once you have selected the formatting type, the system will alert you to the loss of data, confirm the action and wait for the process to be completed, do not interrupt the phone at this point, and when completed, the card will be ready to write files in the selected mode.
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Use UHS-I speed class cards (U1 or U3) for Redmi 9. Slow cards (Class 4, Class 6) can cause interface lags and long application downloads.
Configuring access rights and working with files
After formatting, you need to make sure that the applications have permission to write data. Modern versions of Android (10 and above), on which Redmi 9 is based, have a strict security policy. When you first start a gallery, voice recorder or camera, the system can request permission to access media files.
Use a built-in Explorer to manage files. In MIUI, it's simply called Explorer and has a user-friendly tab interface. If you use third-party file managers like Total Commander or Files by Google, make sure you give them access to all files on the device when you first run them. Without that, file access will be limited to system folders only.
| Type of access | Description | Where to change |
|---|---|---|
| Reading/Recording | Full access to save photos, music | Settings → Applications → Permissions |
| Only reading. | It is impossible to save new files | Checking rights in the Conductor |
| System access | Access to operating system and cache | Automatically when formatting |
Transfer applications to SD card
One of the main goals of memory expansion is to install games and programs. However, starting with Android 6.0, it is up to app developers to decide whether to transfer them to an external medium. On Redmi 9, this feature is unstable for many popular applications.
1. Go to Settings → Apps → All Apps →
2. Select the desired application from the list.
3. Find the memory or storage button.
4. If the Change button is active, select SD-map.
⚠️ Note: Moving system applications or mission-critical services (e.g. Google Play Services) to SD-The card can lead to unstable operation of the phone and the appearance of errors.
If the transfer button is missing or inactive, the developer has banned this action, in which case only media files (photos, videos, music) can be transferred to the map, freeing up the internal space. USB and ADB-commands for forced transfer, but it requires technical skills and can disrupt application updates.
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Not all applications support the transfer to SD-map due to Android security restrictions. Target the presence of an active "Change" button in the settings of a particular application.
Problem Solving: The map is not defined or requires formatting
Redmi 9 can be a problem when it stops seeing a map or constantly writes "Formatting required" for several reasons, and often the problem is with the file system: if the card is formatted on a computer in NTFS or exFAT format with a non-standard cluster size, the phone may not recognize it.
Also worth checking is the physical status of the contacts. Oxidating the gold contacts on the card or getting dust into the phone slot disrupts the connection. Try gently wipe the contacts of the card with a soft eraser or an alcohol wipe. If the problem persists, try formatting the card on your computer to a FAT32 file system (for cards up to 32 GB) or exFAT (for cards up to 64 GB and up) with a default cluster size.