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Is your Android device low on space? If your phone has a MicroSD card slot, you can use it to expand your space for music, movies or even apps, thanks to the improved SD card features in Android 6.0 Marshmallow.

This seems like a big change for Google. After shunning SD card slots in Nexus devices and recommending manufacturers stay away from external storage, Android is now beginning to better support them.

Portable vs. Internal Storage

Related: How to Buy an SD Card: Speed Classes, Sizes, and Capacities Explained

There are two ways to use an SD card with your device. In the past, Android has traditionally used all SD cards as portable storage. You can remove the SD card from the device and plug it into your computer or another device and transfer files, like videos, music, and photos, back and forth. Your Android device will continue working properly if you remove it.

Starting with Android 6.0 Marshmallow, though, some phones can use SD cards as internal storage as well. In this case, your Android device "adopts" the SD card as part of its internal pool. It'll be treated as part of your internal storage, and Android can install apps to it and save app data to it. In fact, since it's considered internal storage, any type of app can be installed to the SD card--including apps that provide widgets and background processes. Unlike older versions of Android, it doesn't matter whether the developer has disabled the "move to SD card" permission or not.

However, when you use an SD card as internal storage, Android formats the SD card in such a way that no other device can read it. Android also expects the adopted SD card to always be present, and won't work quite right if you remove it. This method is useful if your phone doesn't come with very much space to begin with, and you want more space for your apps and files.

In general, it's probably most convenient to leave MicroSD cards formatted as portable storage. if you have a small amount of internal storage and desperately need room for more apps and app data, making that microSD card internal storage will allow you to gain some more internal storage. This comes at the cost of flexibility and possibly slower speed, if the card is slower than your device's internal storage.

How to Use an SD Card as Portable Storage

Let's say you want to use your SD card or flash drive as portable storage--to watch a movie on your device, or to offload photos and videos that are taking up too much space.

Insert the card it into the microSD slot on your device. You'll see a notification indicating your SD card or USB drive was detected. If it's an SD card, you'll see a "Set Up" button.

You can then select "Use as portable storage," and you'll keep all the files on your device.

Related: How to Use Android 6.0’s Built-in File Manager

To view the contents of the drive, tap the "Explore" button in the notification that appears afterwards. You can also head to Settings > Storage & USB and tap the name of the drive. This will open Android's new file manager, allowing you to view and manage the files on the drive. You can also use other file manager apps, of course.

The "Eject" button allows you to safely remove the drive.

How to Adopt a MicroSD Card as Internal Storage

If you plan on adopting an SD card as internal storage, you'll want to first ensure you're using a speedy SD card. Not all SD cards are equal, and a less expensive, slower SD card will slow down your apps and phone. It's better to pay a few extra bucks for some speed. When adopting an SD card, Android will test check its speeds and warn you if it's too slow and will negatively impact your performance.

To do this, insert the SD card and select "Setup." Choose "Use as internal storage."

NOTE: Android will erase the contents of the drive, so be sure you've backed up any data on it.

You can then choose to move photos, files, and some apps to the new device, if you like. If not, you can choose to migrate this data later. Head to Settings > Storage & USB, tap the drive, tap the menu button, and select "Migrate data."

How to Change Your Mind

You'll also see the storage device in the Settings app. Open the Settings app, tap the "Storage & USB" option, and you'll see any external storage devices appear here.

To turn a "portable" SD card into internal storage, select the device here, tap the menu button in the top-right corner of your screen, and select "Settings." You can then use the "Format as internal" option to change your mind and adopt the drive as part of your device's internal storage. This will erase the contents of the drive, so be careful and ensure you have everything backed up first.

To make an "internal" SD card portable so you can remove it from your device, visit Settings > Storage & USB, tap the device's name, tap the menu button, and tap "Format as portable." This will erase the contents of the SD card, but you'll be able to use it as a portable device afterwards.


Android's improved support for MicroSD cards is nice, but you're probably better off with speedy internal storage than a MicroSD card formatted to function as internal storage. That SD card will likely be a bit slower.