Dose putting a micro SD card in your android phone allow the OS to mount the SD card and use the storage space the same way it would internal memory eg. photos taken on the phone would be saved to the micro SD card. Or does the android OS treat the micro SD card as an "external storage source" the same way a laptop treats an external USB flash thumb drive ?

The phone in question is a Samsung Galaxy J5 2016.

If its not possible to mount the external storage and use it like "internal storage" is it possible to set that all photos are to be stored on the external storage as this is whats taking up most of the room on the phone.

  • This depends on the vendor. For example Samsun blocks some functionality the sd card allows in stock android because they claimed it would confuse users.
    – William
    May 5, 2018 at 18:55
  • @William - thanks ive updated the question to add the phone make / model
    – sam
    May 5, 2018 at 19:53
  • Adoptable storage is the term I believe you are looking for. It isn't enabled by default.
    – William
    May 5, 2018 at 22:44
  • What Android version are you using and is your phone rooted tor not? May 7, 2018 at 20:15
  • If you are just looking for saving photos to sd-card: android.stackexchange.com/a/106519/143375 May 8, 2018 at 0:25

3 Answers 3


Since Android 6.0 (Marshmellow), Android supports Adoptable Storage. However, many phone manufacturers, including Samsung, have disabled this feature on their phones.

How to use Adoptable Storage on supported devices:

If you do have a phone that supports this feature, you can turn it on by following these instructions:

  1. Put an SD card in your device.
  2. Open "Settings", "Storage", the SD card, click the three vertical dots, and press "Storage Settings".
  3. Tap "Format as Internal".

What it does:

Here's how Adoptable Storage works, according to source.android.com:

When external storage media is adopted, it’s formatted and encrypted to only work with a single Android device at a time. Because the media is strongly tied to the Android device that adopted it, it can safely store both apps and private data for all users.


Apps can be placed on adopted storage media only when the developer has indicated support through the android:installLocation attribute. New installs of supported apps are automatically placed on the storage device with the most free space, and users can move supported apps between storage devices in the Settings app. Apps moved to adopted media are remembered while the media is ejected, and return when the media is reinserted.

So not only does the device have to support Adoptable Storage, but the apps have indicate support for it too to be able to be stored on the SD card.

  • Thanks @Flimm when you say "Samsung have disabled the feature on their phones", and then "How to turn it on" below are you referring to how to turn it on, on Samsung phones or how to turn it on, on phones that allow it only ?
    – sam
    May 6, 2018 at 11:58
  • @sam google it. Experiment. I have tried enabling this using adb through terminal and it didn't work. Most likely this is not changeable on a large majority of Samsung phones.
    – William
    May 6, 2018 at 17:13
  • @sam I edited my answer to clarify the first heading.
    – Flimm
    May 7, 2018 at 12:14

No, in Android Micro-SD is taken as an external device. Also in the context of your question if you are talking about programming an Android App, Google doesn't recommend to use an external Device, because they are temporary storage. They Say:-

Every Android device supports a shared "external storage" space that you can use to save files. This space is called external because it's not a guaranteed to be accessible—it is a storage space that users can mount to a computer as an external storage device, and it might even be physically removable (such as an SD card). Files saved to the external storage are world-readable and can be modified by the user when they enable USB mass storage to transfer files on a computer.

So before you attempt to access a file in external storage in your app, you should check for the availability of the external storage directories as well as the files you are trying to access, then perform your operation in it.

For more info, see the official Android developer documentation on data storage.


Because you have a Samsung phone there is no easy (offical) way to format your sd-card as Adoptable Storage if it's that you are looking for.

However using adb it's still possible:

  1. Connect your phone (with insert sd-card) to your computer and make sure USB-Debugging is allowed
  2. Open adb-shell (How you do that it matters what OS are you using on your computer your phone is connected)
  3. Type sm list-disks then it outputs the name/ value of your sd-card
  4. Use sm partition <DISK> private and put the disk-value in that it looks like: sm partition disk:179 private
  5. Then restart using: reboot
  6. Now it shares the internal-storage with the sd-card and when you install apps it fills up internal and sd-card in a relation 50:50

Notice that all of your data on the sd-card gets erased. I don't know if it's also erase your internal (it depents on device and android-version). Also your memory will not anymore be displayed correctly as you can see here. There is no root required but it won't work on every device. Some users say it works others say it doesn't. At least you can try it.

BTW. here is a guide how you install and open adb-shell for every common OS, if you don't know how to do that!

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