Full Memory Card Check on Xiaomi Phone: From Errors to Speed

Why it’s important to check your memory card on Xiaomi and when to do it

MicroSD cards in Xiaomi smartphones are not just additional storage, but a potential source of problems. From sudden read errors to complete data loss, the consequences of using a poor-quality or damaged card can be serious, especially for Redmi Note, POCO and flagship Xiaomi 13/14 models, where microSD is often used to store high-resolution photos, 4K videos or even port applications.

Check the memory card in several cases: 1) After purchase - to exclude forgery (especially if the card is purchased on marketplaces such as AliExpress or from unofficial sellers). 2) When errors such as "SD- card is damaged" or "Unknown format. 3) If the Xiaomi phone began to slow down when writing files or the card is suddenly unmounted. 4) Before important operations - for example, before shooting video on Xiaomi 13 Ultra in the format 8K or transferring applications to the card.

In this article, we will discuss 5 working methods of verification, from standard MIUI tools to professional utilities, as well as learn how to recognize fakes and fix typical errors. All methods are tested on current MIUI 14/15 firmware and work on most Xiaomi models, including Redmi 12, POCO F5 and Xiaomi 14 Pro.

Method 1: Integrated diagnostics in MIUI

MIUI has a hidden tool for checking external drives that is available without installing third-party applications, which is suitable for quick testing for file system errors and phone compatibility.

1. Connect the memory card to your phone (if it is not already inserted).
2. Go to Settings → Memory (or Storage depending on the version of MIUI).
3. Slip on the item "SD- card" (or the name of your card).
4. In the upper right corner, press three dots (⋮) and select "Storage settings".
5. Scroll down and find the “Verify and Correct” option (or “Diagnostics” on newer versions).

The system will offer two options: "Verification" - scans the card for errors (takes 1-3 minutes). • "Fix" - automatically eliminates the problems found (can delete corrupted files).

⚠️ Warning: If after checking the phone offers to format the card, don't agree right away. First copy all the data to the computer or the cloud. Formatting in MIUI uses the default exFAT file system, which may not be optimal for cards less than 64 GB (preferably select FAT32).

This method doesn't test read/write speeds or detect fakes in real volume, but it's going to need other methods, which we'll talk about later.

Backup of important data

Charge your phone at least 50%

Close all applications that work with the map (gallery, music players)

Make sure the card is inserted correctly (contacts are not contaminated)-->

Method 2: Checking the read/write speed

A slow memory card can cause lags when shooting videos, downloading apps for a long time, or even damaging files. For example, to record video in 4K@60fps on the Xiaomi 13T Pro, a card with a write speed of at least 30 MB / s is required.

• 📱 A1 SD Bench is a simple application with a minimalist interface that shows read/write speeds in MB/s.
• 📊 AndroBench is a more advanced tool with random/sequential access tests (useful for evaluating performance in games).
• 🔍 SD Card Tester – checks not only speed, but also stability of operation (identifies “sinking” performance).

Instructions for the A1 SD Bench (recommended for most users):

1. Install the app from Google Play.
2. Launch and select your SD- card from the list of drives.
3. Press Start Benchmark and wait until the test is completed (1-5 minutes).
4. Compare the results with the declared characteristics of the map (see the table below).

If the actual speed is below the stated by more than 30%, the card is either fake or badly worn, for example, if your SanDisk Extreme U3 is recording at 15 MB/s instead of 90 MB/s, that’s a reason to replace it.

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On Xiaomi phones with UFS 3.1 support (such as Xiaomi 14), the memory card read speed may be limited by the controller.

Method 3: Real volume verification (detection of fakes)

One of the most common problems is an overcapacity memory card, for example, instead of the promised 128 GB, the real volume can be 16 GB, and the rest of the space is "emulated" by the controller, and when you write files above the real limit, the data is simply erased without warning.

To detect fraud will help the utility H2testw (for Windows) or FakeFlashTest (for Android).

On a computer (H2testw)

1. Connect the card to the PC through the card reader.
2. Download H2testw (portable version does not require installation).
3. Start the program, select the drive letter of your SD- card.
4. Click on "Write + Verify" and wait until it's finished (may take hours for larger cards).

If the message “Warning: Only X GByte OK” appears at the end of the test, your card is fake and X is the actual size of the card.

On the phone (FakeFlashTest)

1. Install FakeFlashTest from Google Play.
2. Select the SD- card and click "Start Test".
3. The application will fill the map with test files and check their integrity.

⚠️ Warning: The test erases all data from the card! Make sure to back up before checking. Also note that on 256 GB+ cards, the test can take more than 4-5 hours.

Critical: Fake cards are often sold under SanDisk, Samsung or Kingston brands with labels like "Premium" or "Ultra"; check the package for holograms and only buy from official dealers.

Method 4: File system check and error correction

If the memory card is detected by the phone, but the files are not read, disappear, or errors like "File corrupted" appear, the problem may be in the file system, most often after:

• 🔌 Incorrectly retrieved card (without "Safe Retrieval").
• 📵 Sudden power outage during recording.
• 🖥️ Connect to a virus-infected computer.

This can be corrected in two ways:

Option 1: via telephone (MIUI)

1. Go to Settings. → Memory. → SD-map → Storage settings.
2. Select "Format" and confirm the action.
3. After formatting, select the file system: • FAT32 - for cards up to 32 GB (maximum file size - 4 GB). • exFAT - for cards 64 GB or more (supports files > 4 GB).

Option 2: Through a computer (CHKDSK)

If the phone doesn’t see the card or gives a formatting error:

1. Connect the card to the PC.
2. Open the Command Prompt on behalf of the administrator.
3. Enter the command (replace X with the letter of your drive):

chkdsk X: /f /r

Where: /f corrects errors, /r repairs damaged sectors.

If CHKDSK doesn't help, try formatting the card in SD Formatter, the official utility from the SD Association.

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Formatting in exFAT is mandatory for 64GB+ cards, but can cause compatibility issues with some devices (e.g. older cameras).

Method 5: Wear test (for used cards)

Memory cards have a limited record life — usually 10,000 to 100,000 cycles depending on the type of memory (MLC, TLC, QLC). If you buy a used card or use it for several years, it is worth checking the degree of wear and tear.

This is the case with FlashID (Android) or CrystalDiskInfo (Windows), an example of checking on your phone:

1. Install FlashID.
2. Select the SD- card and wait for the data to be read.
3. Pay attention to the parameters: • Total LBAs - total number of sectors. • Bad Blocks - number of broken blocks (should be 0). • Wear Leveling Count - level of wear (the higher, the worse).

If the number of Bad Blocks exceeds 5-10, it is better to replace the card.

• 📉 The write speed drops when the card is filled by more than 80%.
• 🔄 The card is often unmounted when working hard.
• 🚨 There are not enough space errors on a nearly empty map.

To extend the life of the memory card, follow simple rules: • Do not fill it more than 90%. • Avoid frequent formatting (better use Safe Removal). • Do not store the card in high humidity or temperature (for example, near the phone battery).

Common Memory Card Errors on Xiaomi and How to Fix Them

Even the original cards can cause problems on Xiaomi smartphones, and consider the most common errors and ways to fix them:

If none of the methods worked, the problem could be in the hardware: • A faulty card slot in the phone (often found after falls or moisture). • The card controller is out of order (characteristic of cheap no-name cards).

In such cases, only a card replacement or phone repair remains.

FAQ: Frequent questions about memory cards on Xiaomi