Android Enthusiasts Stack Exchange is a question and answer site for enthusiasts and power users of the Android operating system. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

If I pull out my storage card, my device complains that the card was removed unexpectedly, and that I must "unmount" it first.

After googling, I found out that this is some Unix term for breaking the connection between the system and the storage so there is no data in memory that was not yet written to the storage.

However, I have not found an easy way to do this. There is a command, but it is buried in Settings!

Since users are expected to notify the device before pulling out a card, there must be a quick, easy way to do so.

Should I power down the phone? That takes more time to execute, but less effort (fewer strokes).

Come to think of it, with all the devices I have used in the past (cameras, music players), I would power down the device before changing SD cards, but those devices all have nearly instantaneous shutdown and startup times.

share|improve this question

Unmounting an SD card is comparable to the "Safely remove device" feature of Windows, which should be used when removing USB drives etc.

If you remove the device without notifying the OS that the connection is going to be lost, some data may not be written to the device, and corruption and data loss can occur. This is because the OS uses buffers to store the data before transferring it to the device itself.

Even though the operation appears to be complete, there still may be some data left in the buffer and waiting to be written to the device. Unmounting/safely removing the device forces there buffers to be written to the device before removal, thus preventing corruption.

I'd recommend either getting used to going through the menus to unmount the SD, or if your device supports, using a widget like Eject SD for easier access. Powering off the device works too, but as you mentioned, it's a bit slower.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.