What happens if you take out SD card without unmounting?

What is Unmounting?

Unmounting refers to the process of safely preparing an SD card for removal from a device like a phone, camera, or computer. It ensures that all writes to the card have finished before disconnecting it.

The purpose of unmounting an SD card before removing it is to prevent data corruption or damage. When a card is mounted, the operating system is accessing it and writing data. If you remove it without unmounting, you risk interrupting critical read/write processes before they are complete. This can cause file system corruption, data loss, or even permanent hardware damage.

Essentially, unmounting signals to the device that the SD card is going to be disconnected, allowing it to finish any pending operations and prepare for safe removal. It is an important step to avoid potential issues.

Immediate Effects

Removing the SD card without properly unmounting it first can lead to some immediate effects on your device. One common issue is that the screen may freeze or become unresponsive right after removing the card. This is because the operating system is still trying to access data on the now-missing SD card.

You may also see error messages pop up related to the sudden “removal” of the SD card. On Android devices, you may see a message like “SD card removed unexpectedly” or “SD card unmounted.” On other devices like cameras, you may see an error that files are corrupted or cannot be accessed.

Overall, the device can become laggy or unresponsive if you remove an SD card without unmounting. This is because the operating system gets confused when the card suddenly disappears, especially if data was actively being written to or read from the card.

Data Corruption

Removing an SD card without properly unmounting it first risks corrupting the data stored on the card. This is because the operating system may still be in the process of reading from or writing data to the card when it is suddenly removed. According to BleepingComputer, if you directly pull out the SD card during a read/write operation, it can corrupt the files and make them unreadable.

When a file is open or in use, parts of it may be temporarily stored in the device’s RAM. If the SD card is removed mid-operation, the file transfer gets interrupted before it can be fully written to the card. This results in corrupted or partially written data that the device is unable read later on. The corruption can affect anything from individual files to the file system structure itself.

To avoid data corruption, it’s critical to properly unmount the SD card first before removing it. This ensures any pending read/write operations are fully completed and closed before disconnecting the card. Trying to access corrupted files or a damaged file system can also introduce problems to the host device itself in some cases.

File System Damage

Removing the SD card without properly unmounting it can cause file system damage in the form of fragmentation, lost clusters, and directory errors. File system fragmentation happens when files are broken into pieces and scattered across the SD card rather than stored contiguously. This slows down file access and makes it more difficult for the operating system to keep track of file contents. Lost clusters refer to groups of disk sectors that are marked as allocated for file storage in the file system but contain outdated or garbage data because the operating system lost track of them. Directory errors can also occur, such as invalid file paths, missing files or folders, and incorrect free space reporting. These issues stem from the file system metadata becoming unsynchronized with the actual contents of the SD card when suddenly removed.

According to Quora, interrupting SD card operations by removing it without unmounting can corrupt partially written files, overwrite other files, and leave file system structures in an inconsistent state [1]. On Reddit, a user explains that any files still cached in memory that have not yet been written to the SD card could be lost if it is suddenly removed [2]. Overall, file system damage reduces performance and data integrity until the file system is repaired.

Device Damage

Removing an SD card without properly unmounting it first runs the risk of causing electrical and physical damage to both the card and the device reading it. This is because when a card is mounted, the device’s memory controller maintains an electrical connection to the card’s flash storage and controller chip. Suddenly interrupting this connection by yanking out the card can potentially short-circuit components and cause permanent hardware failure.

Specifically, the most vulnerable components are the SD card’s controller chip and the memory card host controller inside the device. These act as liaisons between the SD card slot and the main system components. Abruptly cutting the power during a read/write operation can fry these controllers. The SD card itself can also become corrupted or unusable if critical data or file tables are damaged. While modern SD cards and devices have some protections against this, there’s still a risk of catastrophic failure that necessitates the proper unmounting procedure.

Overall, it’s impossible to predict the extent of electrical or physical damage caused by improper removal of an SD card. The system may continue functioning normally, or it could result in permanent irreparable damage. Following the proper unmounting steps helps ensure the integrity of data and hardware whenever removing external storage media.

Recovering Data

If you accidentally remove an SD card without properly unmounting it first, the data on the card can become corrupted or damaged. Thankfully, there are software solutions that can help you recover lost files and photos in many cases.

Recovery software like Stellar Data Recovery is designed to scan SD cards and restore corrupted, deleted, or lost files. These programs work by scanning the raw data on the card and reconstructing files and directories. They can often recover photos, videos, documents, and other file types.

The key is to avoid saving new data to the SD card before running recovery software. Overwriting the card with new files makes it much harder to recover older data. Immediately connect the corrupted SD card to your computer and run recovery software to get the best results.

With the right software, you have a good chance of restoring your files after removing an SD card without properly unmounting it. Just don’t save new data to the card, and let recovery software do its job.

Preventing Issues

Following the proper unmount procedure before removing an SD card is crucial to avoiding potential problems. Most operating systems have a “safe remove” feature that will unmount the SD card before physically removing it.

On Windows, right-clicking the SD card icon in File Explorer and selecting “Eject” will safely disconnect the card. Mac users can right-click the icon on the desktop or in Finder and select “Eject”. For Android devices, go to Settings > Storage and tap the “Unmount” button next to the SD card name.

This safe remove process ensures any pending writes to the card are completed, then disconnects it from the operating system. Simply pulling out the card without warning could interrupt a file transfer or filesystem update, leading to anything from minor data corruption to complete drive failure.

Following this proper unmount procedure every time eliminates almost all risk when removing external storage like SD cards. The minor time investment is well worth avoiding disastrous consequences like permanent data loss. Embrace safe removal features, and eject external storage properly.

Alternatives to Unmounting

While unmounting an SD card before removal is always the safest option, there are some alternatives in certain situations:

If you need quick, temporary access to the files on the SD card, you can simply remove the card and then reinsert it. This avoids having to go through the unmounting process, but does risk possible data corruption or other issues if you aren’t careful. It’s best to only do this when absolutely necessary and when you plan to remount the card soon after.

On Android devices that don’t give you a clear “unmount” option, you may be able to achieve the same effect by going into the Storage settings and toggling the SD card off and then on again. This essentially mounts and unmounts it, allowing you to safely remove it after. Just be sure to fully turn it off before removal.

Using a dedicated SD card reader can allow quick removal as well, as the card is unmounted when removed from the device itself. Just be sure to properly eject the card from the computer before physically removing it from the reader.

In general, it’s wisest to just take the extra few seconds to properly unmount an SD card before removing it, in order to prevent any possible data issues or corruption. The alternatives have their risks.

Troubleshooting Problems

If you remove your SD card without properly unmounting it first, you may experience issues like data corruption, device damage, or errors. Here are some steps you can take to diagnose and fix any problems:

First, reinsert the SD card into your device and see if it is detected properly. If you get an error like “SD card unexpectedly removed,” try rebooting your device and reinserting the card. This may resolve simple mounting issues.

Scan the SD card with antivirus software to check for malware or corruption. Tools like Windows Defender can identify and quarantine infected files.

Use data recovery software like Recuva or EaseUS Data Recovery Wizard to scan the SD card and restore lost files. This may salvage photos, documents, or other data.1

For serious file system corruption, you may need to format the SD card. This will erase all data but may fix the corruption. First try to recover any important files using data recovery software.

If your device won’t recognize the SD card at all, the card itself may be damaged. Try inspecting the contacts and using a different card reader. Severely damaged cards may need professional data recovery services.

Going forward, remember to always use the “Safely Remove Hardware” option before taking out your SD card. This can prevent many common issues.


In summary, it is always important to properly unmount your SD card before removing it from your device. Unmounting prepares the operating system to disconnect the SD card by flushing any cached writes and locking the drive to ensure no further writes occur. Removing the card without unmounting risks data corruption, file system damage, and potential harm to your device.

The main points to remember are:

  • Unmounting prevents data loss and hardware issues.
  • Removing an SD card without unmounting can corrupt files or damage the file system.
  • Always use the “Eject” or “Unmount” option in your device’s interface before removing a card.
  • If you encounter problems, try data recovery software or reformatting, but issues are best avoided by proper unmounting.

Following this simple but important practice will help ensure your external storage media continues working smoothly.

Leave a Comment