Have you inserted a microSD into your smartphone, but Android stubbornly ignores it? Or did the card suddenly stop being detected after a system update? Problems with reading external drives are one of the most common problems on devices running Android. According to statistics from service centers, up to 30% of calls with “non-working storage” are associated specifically with memory card errors, and not hardware failures.

In this article we will analyze all possible reasons - from banal contamination of contacts to file system failures. You will learn how to diagnose the problem, which settings to check first, and what to do if a memory card SanDisk, Samsung EVO or another brand is not recognized. And most importantly, what actions can exacerbate the situation lead to irretrievable loss of data.

Spoiler: in 80% of cases the problem is solved without contacting a service center. But there are also pitfalls - for example, incorrect formatting it can make the card incompatible with your device. Therefore, read carefully and follow the instructions in order.

1. Checking the physical condition of the card and slot

Before digging into the settings, make sure that the problem is not mechanical. Start with a visual inspection:

  • 🔍 Card contacts: In a bright light, check for scratches, oxidation, or dirt on the microSD gold contacts. Even a thin layer of dust can interrupt the connection.
  • 📱 Card slot: Insert and remove the card when the phone is turned off. If the slot is wobbly or the card fits in too loosely, this is a sign of wear on the connector.
  • 🔄 Test on another device: try inserting the card into another smartphone, tablet or card reader. If it is not detected everywhere, the problem is in the card itself.

If there are dirt on the contacts, gently wipe them soft eraser (for pencils) or with a cotton swab dipped in isopropyl alcohol. Do not use acetone or other aggressive solvents! To clean the slot, you can use dry toothpick, but without pressing - do not damage the contacts inside.

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If the card was inserted into the phone during a fall or impact, there is a high probability of microcracks on the board. In this case, data recovery is only possible in the laboratory.

Pay attention to indication: some devices (for example, Samsung Galaxy or Xiaomi Redmi) show a notification when a card is inserted. If it is not there, this is an indirect sign of problems with the slot or memory controller.

2. Reboot and check system settings

Often the problem is solved by a simple reboot. But if this does not help, check the system settings:

  1. Open Settings → Storage (or Memory).
  2. Scroll down - if the card is detected but not mounted, you will see it in the list marked "Damaged" or "Unknown format".
  3. Click on the card name and select Customize or Format (if the data is not important).

If the card is not displayed even here, try reset storage settings:

Settings → System → Reset → Reset application settings

This will not delete your data, but it will reset permissions for applications that may have blocked access to the card. For example, after updating to Android 13 many users were faced with the fact that the system required re-allowing access to the storage for the file manager.

📊 Your memory card stopped working after
Android update
The phone was hit/dropped
Extractions during recording
On its own
Other

3. Formatting a memory card

If the card is detected but not mounted, the most reliable solution is Format. However, remember: this will delete all data! If there are important files on the card, first try to extract them through the card reader on your PC.

Android supports three file systems for microSD:

File systemMax. card sizeCompatibilityFeatures
FAT32up to 32 GBAll devicesDoes not support files >4 GB
exFATup to 128 PBAndroid 6.0+Optimal for cards >64 GB
NTFSup to 16 EBPartialRequires root or supported kernel

To format the card directly in your phone:

  1. Go to Settings → Storage → [Card name].
  2. Click Format (or Clear).
  3. Select exFAT for cards >32 GB or FAT32 for compatibility with older devices.

If the phone does not offer a choice of file system, format via PC:

  • 💻 Connect the card via a card reader.
  • 🖱️ In "This Computer" right-click on the card → Format.
  • ⚙️ Select exFAT (recommended) or FAT32.
What should you do if Windows asks you to format the card when connecting?

This is a sign of damage to the file system. Do not format it right away! data-i="121">or TestDisk or PhotoRec, and then format it.

4. Checking the card for errors via PC

If the card is detected on the computer, but does not work on the phone, check it for errors using the built-in tools of Windows or macOS.

For Windows:

  1. Connect the card via a card reader.
  2. Run Command line as administrator.
  3. Enter the command: 
    chkdsk X: /f /r

    where X is the letter of your card.

For macOS:

  1. Open Disk Utility (via Spotlight).
  2. Select the card in the left menu → First Aid → Run.

If utilities find errors but cannot fix them, the card is most likely physically damaged. In this case, only replacement will help.

☑️ Checking the card on a PC

Done: 0 / 4

5. Configuring the card as internal or external storage

In Android 6.0 Marshmallow and newer, the memory card can be used as expansion of internal memory (Adoptable Storage). However, this mode has limitations:

  • ⚠️ The card will be encrypted and tied to the device - it cannot be read on another phone.
  • ⚠️ After removing the applications installed on it will stop working.
  • ⚠️ Not all manufacturers support this mode (for example, Huawei and Xiaomi often block it).

To configure the card as internal memory:

  1. Insert the card into the phone.
  2. When a notification appears, click Setup → Use as internal storage.
  3. Follow the system instructions (formatting will be required).

If you want to return the card to external storage mode:

  1. Go to Settings → Storage → [Card name].
  2. Click on the three dots in the upper right corner → Data transfer and formatting.
  3. Select Format as external.
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The "internal memory" mode is convenient for installing applications, but makes the card incompatible with other devices. Use it only if you are sure that you will not remove the card.

6. Problems with firmware and updates

Sometimes the map is no longer detected after updating Android. This is due to bugs in new kernel versions or storage drivers. For example, after updating to Android 12 many users Samsung Galaxy S21 complained about problems with cards SanDisk Ultra.

What you can do:

  • 🔄 Roll back update: if the problem appeared recently, try returning the previous firmware version (look for instructions for your model).
  • 📱 Reset settings: reset to factory settings (don't forget to make a backup!).
  • 🛠️ Install a custom kernel: for advanced users - some custom kernels (for example ElementalX) work better with external ones drives.

Before resetting, check if access to the card is blocked by antivirus or cleaning application (for example, Clean Master or 360 Security). Go to their settings and temporarily disable storage protection.

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If the problem appeared after the update, check the forums for your model (for example, 4PDA or XDA-Developers). Often there are already solutions or patches.

7. Hardware faults and when to contact service

If none of the methods helped, the problem is most likely hardware. Here are the signs that you can’t do without a service center:

  • 🔌 The card is not detected on any device (including PC).
  • 🔥 The phone overheats when the card is inserted.
  • 💥 Card slot deformed or has visible damage.
  • 🔄 The card is detected, but immediately turns off (cyclic reboot).

Average cost of repairing a memory card slot in service centers:

Type of repairCost (rub.)Timeframe
Cleaning/repairing slot contacts800–1 5001–2 hours
Replacement card slot1 500–3 0001–3 days
Recovering data from a damaged card3 000–10 0003–7 days

If the card is physically intact, but the phone does not see it, the problem may be memory controller on motherboard. In this case, the repair will cost more - from 4,000 rubles and more, depending on the model.

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Before visiting the service center, make a backup copy of the phone’s IMEI (through the engineering menu or applications like MTK Engineering Mode). Sometimes, when repairing a slot, it can be accidentally reset.

FAQ: Frequently asked questions about memory cards on Android

Is it possible to recover data from a card if the phone does not see it?

Yes, but only if the card is detected on the PC. Use apps like Recuva, EaseUS Data Recovery or PhotoRec. If the card is not detected even on a computer, recovery is only possible in the laboratory (cost from 3,000 rubles).

Why does the card work on one phone, but not detected on another?

The reasons may be different:

  • The phone does not support the card capacity (for example, older models do not see microSD >32 GB).
  • The card is formatted in an incompatible file system (for example, NTFS instead of exFAT).
  • Encryption of external drives is enabled on the phone (set in Settings → Security).
How to check if my phone supports memory cards?

Methods:

  1. Look at the specifications of the model on the manufacturer's website (section "Memory").
  2. Use applications like AIDA64 or CPU-Z —they show the supported card types.
  3. Check the presence of a slot physically (on some models, for example, Google Pixelit is not present).
What to do if the card is detected, but the files do not open?

Most likely, The file system is damaged. Try:

  1. Connect the card to the PC and run chkdsk X: /f (where X is the card letter).
  2. Copy the files to your computer, format the card and return the data.
  3. If the files are important, use recovery apps (for example, R-Studio).
Can the card be used as internal memory on all phones?

No. Some manufacturers block this function:

  • Samsung - supports on most models, but may require a branded card.
  • Xiaomi - often blocks Adoptable Storage mode.
  • Huawei - supports only on some models (for example Mate 20 Pro).
  • Google Pixel there is no slot for memory cards.

Before setting up, check the compatibility for your model.