AOMEI Partition Assistant
Micro SD Card Only Showing 30MB! Why & How to Fix
Many factors will lead to the micro SD card only showing 30MB. This article introduces the root causes with giving targeted solutions to recover the full capacity of the micro SD card.
By Irene / Updated on March 25, 2025
User case: Micro SD card only showing 30MB
SD Card Showing as 30 MB on a 32 GB Card. Can't Format, Can't create a partition table
A couple of days ago I received a new 32 GB SD card from Sandisk. Upon arrival, I flashed the Retropie 4.1 image for the Pi Zero onto it. I then put the card into my Pi, and plugged it in. Nothing. It would not boot. I then took it out, and plugged it back into my laptop. The only thing Windows was able to discover was an unknown device, saying that it must be formatted to be used.
Upon further inspection, I realized that Windows was seeing 32 MB of raw unallocated space. I then attempted to create a partition table, and it completes with no errors, but nothing is actually created. Am I screwed and I need to get a new card? Am I doing something stupid? I'm seriously at an absolute loss at what to do, and any help is greatly appreciated.
- Question from raspberrypi.stackexchange.com
A microSD card suddenly showing only 30MB of storage—despite the original capacity of 32GB, 64GB, 128GB, or higher—is a frustrating and confusing issue many users face. This problem often arises unexpectedly, leaving you unable to access your files or use the card for its intended purpose. Whether it’s after formatting, inserting the card into a new device, or purchasing a brand-new card, the sudden reduction to a mere 30MB can stem from various causes, such as incorrect formatting, hidden disk partitions, counterfeit hardware, or even file system corruption. Now, you can get to know more details about the reasons in the following part.
Why is micro SD card only showing 30MB?
The root cause should be necessary to effectively recover your card’s full capacity and avoiding data loss. Below is a table outlining common causes for a micro SD card displaying only 30MB along with explanations and potential solutions:
| Cause | Explanation | Solution |
|---|---|---|
| Incorrect Formatting | The card may have been formatted with a file system (such as FAT16) that limits the partition size. | Reformat the card using exFAT or FAT32. You can use your OS’s built-in utility or opt for AOMEI Partition Assistant to quickly reformat the card. Be sure to back up any data first. |
| Hidden Partitions | Multiple partitions may exist on the card, with only a small (30MB) partition visible. | Delete all existing partitions and create one full-size partition. |
| File System Corruption | File system errors or corruption can cause the card to display a reduced capacity. | Attempt repairs with CHKDSK (Windows) or fsck (Linux/macOS). If problems persist, back up your data and reformat the card. |
| Read-Only Mode | The card or its adapter might have a lock switch enabled, making it read-only and limiting access. | Check the SD adapter’s lock switch. You can also try removing the read-only status using Windows’ diskpart. In some cases, you can adjust partition settings if the issue is software-related. |
| Firmware/Driver Issues | Outdated operating systems or card reader drivers can cause the card’s capacity to be misread. | Update your OS and SD card reader drivers, or try accessing the card on another device. |
| Manufacturing Defect | Physical damage or factory defects may render most of the card’s storage unusable. | Test the card on multiple devices. If AOMEI Partition Assistant and other diagnostic tools confirm consistent issues, it is likely a hardware defect—consider replacing the card. |
| OS Compatibility Issue | Older devices may not support high-capacity SD cards (e.g., SDXC cards over 32GB), leading to misreporting of the available storage. | Check your device’s specifications. If the device isn’t compatible, consider using a smaller capacity card or updating your device. |
To fix the issue of 32GB micro SD card only showing 30MB, you will have X methods. The next part will share the specific steps for you.
How to fix micro SD card only showing 30MB?
The micro SD card only showing 30MB can be fixed in 3 ways. You can follow them and effectively to solve the problem.
Fix 1. Delete the micro SD card partitions
One common cause of a microSD card showing only 30MB is the presence of hidden partitions that limit usable space. These partitions may be created due to improper formatting, firmware updates, or even errors during use. Deleting them ensures that all available space can be reclaimed.
While Windows Disk Management can delete partitions, it sometimes restricts users from deleting certain protected partitions. AOMEI Partition Assistant bypasses these limitations, ensuring a clean reset of the storage space. This multifunctional tool also helps you to perform other operations to fix the micro SD card only showing 30MB issue.
AOMEI Partition AssistantThe Best Windows Disk Partition Manager and PC Optimizer
Step 1. Open AOMEI Partition Assistant, right-click on the OEM partition on the main console, and click “Delete Partition”.
Step 2. You can choose if you need to completely wipe the data on the partition by overwriting it. Choose “Delete partition quickly” or “Delete partition and wipe data on it”.
Step 3. Then, click “Apply” and “Proceed” to commit deleting operation.
Just wait for a while, the process will be completed. Then the deleted partition will be showed as unallocated. And you can create a new partition on it or merge the unallocated space to another partition.
Fix 2. Format the micro SD card
Formatting resets the microSD card’s file system, allowing it to function properly. If the card is incorrectly formatted, it may not be recognized fully by devices, resulting in the problem like the user case that the Sandisk micro SD card only showing 30MB.
Windows Disk Management only allows formatting in FAT32 or NTFS, restricting exFAT formatting in some cases. AOMEI Partition Assistant gives users full control over file system selection.
AOMEI Partition AssistantThe Best Windows Disk Partition Manager and PC Optimizer
Step 1. Install, and run the tool. Right-click the SanDisk SD card partition and choose Format Partition.
Step 2. Here you can choose a file system for it. Six options are offered: NTFS, exFAT, FAT32, Ex2, Ext3 and Ext4.
Step 3. Confirm the operation and click Apply > Proceed to execute it.
Fix 3. Repair corrupted micro SD card via CMD
Although Windows built-in tools have some limitations, they can still be useful in certain situations. For instance, if file system errors or corruption are causing the disk to show reduced capacity like the micro SD card only showing 30MB suddenly, you can use the Command Prompt (CMD) to repair the corrupted card.
Now, insert the problematic microSD card into a card reader and connect it to a working computer running Windows. If your computer is running Windows 10, let’s explore how to fix the damaged SD card without formatting.
Step 1. Open the Search box, type “cmd”, locate Command Prompt, right-click it and choose “Run as administrator.”
Step 2. In Command Prompt window, type “chkdsk d: /f” and hit “Enter”.
Step 3. What you should know is that “d” is the number of drive letter of the partition on SD card. If you don’t know the drive letter assigned to SD card partition, you can go to Disk Management to locate the drive according to its capacity or something else and remember its drive letter. When the process is over, you may repair the damaged SD card successfully and be able to access it in smartphone. If this way is invalid, try the next solution.
Conclusion
A microSD card showing only 30MB instead of its full capacity can be a frustrating issue, often caused by incorrect formatting, hidden partitions, file system corruption, or even hardware defects. While Windows built-in tools like Disk Management and Command Prompt can help resolve some cases, they have limitations in handling advanced partition management and formatting restrictions. AOMEI Partition Assistant offers a more effective solution by allowing users to delete partitions, reformat the card, and repair file system errors with greater flexibility. If your microSD card is experiencing this issue, following the right troubleshooting steps can help restore its full capacity and functionality.
AOMEI Partition AssistantThe Best Windows Disk Partition Manager and PC Optimizer
