Formatting flash drive on Xiaomi Redmi Note 9: 3 proven methods + error solving

Xiaomi Redmi Note 9 remains a popular smartphone even years after its release, and its support for microSD cards up to 512 GB makes the device universal for storing files. However, over time, flash drives begin to “glue”: slow down when writing, give reading errors or completely cease to be determined by the system. In 80% of cases, the problem solves the banal formatting – but how to do it correctly so as not to lose data and not damage the drive?

In this article, we’ll look at all the working ways to format a flash drive on the Redmi Note 9 (including the Note 9 Pro and Note 9S models), figure out which file system to choose for maximum compatibility, and learn how to avoid common errors like “Memory Card is corrupted” or “Could not format”; and also explain why formatting via a PC can be more dangerous than using a smartphone, and how to avoid losing write speed after the procedure.

Preparing the flash drive for formatting: 5 mandatory steps

Before you click Format, make sure you don't delete important data or damage the map itself.

• 📱 Backup. Even if the flash drive is empty, copy it to your PC or the cloud. Once formatted, file recovery will be impossible without specialized software.
• 🔋 Charge your smartphone to at least 50%. interruption of the process due to battery discharge can damage the storage file system.
• 🔍 Check the flash drive for errors. → Click on your card and select "Check." If the system finds errors, it's best to fix them before formatting.
• 🛠️ Use the original adapter (if formatting through the OTG). Cheap adapters may not provide stable nutrition, which is fraught with failures.
• 📌 Remember the capacity of the flash drive. After formatting, the actual volume will be smaller than the stated volume (for example, 64 GB will become ~58GB is normal.

If the flash drive is not detected at all (even after you reboot your phone), try connecting it to another device. If the problem persists, the drive may have physically failed, and formatting won't help, in which case you should contact a service center.

Method 1: Formatting through Xiaomi settings (the most secure)

This method is suitable for microSD cards installed in a smartphone slot, and it is as gentle as possible, since it uses built-in MIUI tools optimized for working with the Xiaomi file system.

Instructions:

1. Open the Settings → Memory.
2. Put it on your flash drive (for example, «SD-map: 128GB»).
3. In the upper right corner, press three dots (⋮) and select "Memory settings».
4. Scroll down and click "Format".
5. Confirm the action, wait until the completion (usually takes 1-3 minutes).

By default, the system will select the FAT32 file system – it is compatible with most devices, but has a file size limit (maximum 4 GB). If you need to record large files (for example, 4K video), choose exFAT (not available on all firmware).

Backup copy of data created

The phone is charged at more than 50%

The flash drive was not removed during work.

Selected the correct file system type-->

⚠️ Warning: If the flash drive is not detected again after formatting, try removing it, restarting the phone and inserting it back in. Sometimes the microSD slot on the Redmi Note 9 "hangs" after surgery.

Method 2: Recovery Mode Formatting (if the phone can’t see the flash drive)

If the memory card doesn't show up in the settings, but the phone physically feels it (e.g., makes a connection sound), you can try formatting it through Restore Mode, which is also useful if standard formatting ends with an error.

Step-by-step:

1. Turn off the Redmi Note 9.
2. Press the Power + Volume buttons up and hold them for 10-15 seconds until the Mi logo and Recovery menu appear.
3. Use volume buttons for navigation and power button for selection. Choose a language (usually English).
4. Go to Advanced → Format SD Card.
5. Confirm the action and wait until it's done. The phone will automatically restart.

In Recovery, formatting is low, which helps to correct file system errors that are not available through standard settings. However, this method does not allow you to choose the file system type - it will be installed by default (usually FAT32).

Method 3: Formatting via PC (Windows/macOS/Linux)

This method is suitable for OTG-If you have a flash drive or if the memory card is not formatted via your phone, there are nuances: incorrect settings can lead to loss of write speed or even damage to the drive.

For Windows:

1. Connect the flash drive to the PC through the card reader or OTG-cable.
2. Open “This Computer”, find your drive, right-click and select “Format”.
3. Select the file system: FAT32 for compatibility with all devices (but a 4GB limit per file); exFAT for files larger than 4GB (optimally for the Redmi Note 9); NTFS is not recommended, as MIUI may not work properly with it.

4096 bytes

Start.

For macOS/Linux, use Disk Utility (macOS) or GParted (Linux). The algorithm is similar, but in GParted, you need to apply the changes with the "Apply" button after formatting.

⚠️ Warning: If you format a flash drive through a PC and then paste it into a Redmi Note 9 and your phone asks you to format it again, don't agree. This is a sign of file system incompatibility. Instead format the drive back through your phone (Method 1).

Typical Formatting Errors and How to Fix Them

Even when following instructions, users face problems, and here are the most common mistakes and solutions:

• 🚫 «Failed to format": Try another way (e.g., via PC or Recovery). Check the flash drive for broken sectors with HDDScan or CrystalDiskInfo. If the card is protected from writing, check the physical switch (if any) or use the diskpart command on Windows: Diskpart list disc select disk X (where X is your flash drive number) attributes disk clear readonly
• ⏳ Formatting "hangs" by 0%: Remove the flash drive, restart the phone and try again.If the problem repeats, use the utility SD Formatter from SD Association (you can download it on the official website).
• 🔄 After formatting, the flash drive requires formatting again: This is a sign of hardware malfunction. Try flashing the flash drive controller with Flash Drive Information Extractor (power users only!). If the flash drive is warranty, contact the store for a replacement.

If none of these methods worked, there's probably a problem with the USB stick controller, and in those cases, it's just a replacement drive that helps, and it costs more to repair than to buy a new card.

💡

Before buying a new flash drive, check it for authenticity with H2testw (Windows) or F3 (macOS/Linux) utility. Many of the branded cards on the market turn out to be fakes with understated capacity.

How to Recover Data After Accidental Formatting

If you formatted your USB drive by mistake, don’t panic – there are chances of returning files, but they depend on two factors:

1. Was new information written down after formatting? If so, it will be more difficult to recover the data.
2. What file system was before formatting? With FAT32, recovery is easier than with exFAT.

Instructions for remediation:

1. Remove the flash drive immediately and do not write anything new on it.
2. Connect it to your PC and use one of the programs: Recuva (free, easy for beginners). EaseUS Data Recovery (paid, but with a high recovery rate). PhotoRec (free, works under the name of the newest). Windows/macOS/Linux, Recover even heavily damaged files).

Deep Scan

Save the recovered files to your PC hard drive, not the same flash drive!

The important thing is that the sooner you start recovery, the better the chances are, because once formatted, the data is not physically deleted, it just erases the table of contents of files, and programs restore the information until it has been overwritten with a new one.

💡

Never save your recovered files to the same flash drive – this will result in data loss without the possibility of re-recovery!

Frequent questions about formatting flash drives on Xiaomi