One of the new features in Android 6.0 Marshmallow is the ability to treat microSD cards as if they were internal storage. If you have a cheap phone with 8GB of storage or less, this can let you easily double or quadruple your available storage space for just a few bucks.

But if you’ve got a more expensive phone with a decent amount of built-in storage space, you might want to think twice before formatting a microSD card for use as internal storage, because there are some potentially unpleasant side effects.

adopt storage

Android app developer StereoMatch did a little experimenting and discovered a few things about the way Android 6.0 lets you adopt external storage devices as internal storage that aren’t really all that clear from Google’s description.

In a nutshell, when Android 6.0 sees that you’ve inserted a microSD card the operating system will ask if you’d like to treat it as portable storage or as internal storage.

If you choose portable storage, it’ll be treated the same way as removable storage devices have been for the past few versions of Android: you can’t easily install apps to the storage card, but some app data can be saved there and you can store music, movies, photos, and other content on the microSD card.

Choose internal storage and the microSD card will be reformatted and encrypted. Once this is done, the card can only be used as internal storage. If you try to eject the card and read it on a computer, it won’t work. All data on the card will also be erased, so you may want to back up anything important first. Android does provide an option to migrate it, but early reports suggest it’s unreliable.

After you’ve formatted your microSD card, your phone will treat it as your primary storage space. In fact, if you navigate to the Storage & USB section of your Android Settings, you won’t even see how much internal storage space is available anymore. You’ll only see free space on your microSD card. And if you use a file browser to navigate internal storage, it’ll only show your microSD card — there’s no simple way to copy files to and from the real internal storage. you’ll be able to see how much storage is used and how much is free — but you can only explore the SD card storage, not the internal storage. And if you use a third-party file explorer or connect your device to a computer, you won’t be able to navigate to internal storage at all.

You can still choose to have apps installed to either the true internal storage or your microSD card that’s been formatted to behave like internal storage. But if you had a phone with 8GB of storage and a 32GB microSD card, you’ll only have 32GB of space for music, movies, games, or other files, not 40GB.

Here’s why this matters: the built-in storage is almost certainly faster than any microSD card you’re using. You’ll see the biggest hit if you try to install apps to the removable storage card. But even with files and data loaded on the microSD card, your device might perform some tasks more slowly.

So if you’ve got a phone with 32GB of fast storage, you’ll probably want to avoid formatting your microSD card as if it were internal storage. It’d restrict your ability to access your speedier eMMC storage.

On the other hand, if you’ve got a cheap Android One handset or another device with just 4GB or 8GB of built-in storage, you might be willing to trade off a slight decrease in speed for a big boost in the amount of available storage space.

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45 replies on “Android 6.0 can treat SD cards as internal storage… at a cost”

  1. I already use sd card as a internal storage.but please tell me how to access internal storage

  2. I have got samsung J5 with 8 GB internal storage only, I was able to install only few apps to my device that was so annoying and frustrating. Then I came to know that we can use our SD card as internal storage, I immediately order for Strontium 32 GB Class 10 Ultra High Speed SD Card and rooted my device because samsung didn’t provided feature to use SD card as internal storage and somehow I was able to use SD card as internal storage.
    And Guess What? My SD Card got corrupted after a month. I searched on web about the issue and I found that normally feature of using your SD card is not at all reliable. Due to some encryption SD card can get corrupted at any time.
    Due to lifetime warranty on SD card I got my SD card replaced, but now I just use my SD card as portable storage and just move all downloaded apps manually to SD Card by Link to SD App (Rooted only).
    Guys Please also take care about using your SD Card as internal storage.

  3. I have formatted my SD card as internal storage for Moto E3,now i can’t add music from my laptop.
    Any help would be appreciated.

  4. “you’ll be able to see how much storage is used and how much is free — but you can only explore the SD card storage, not the internal storage. And if you use a third-party file explorer or connect your device to a computer, you won’t be able to navigate to internal storage at all.”

    I’m able to explore both the SD card and internal storage without any issue on both my Macbook and on my phone using unrooted Android 6 with SD card as storage, using GPE HTC one M8.

    Perhaps an update of this article is needed?

  5. This feature doesnt work on me, when I tap “use as internal storage” the progress bar gets stuck at 20% the closes. Anyone got a fix?

  6. Does anybody have any idea how to copy files to and from computer (PC) after using SD card as internal storage??

  7. I did this to an LG under 4.1 two years ago, only my results were better.

    Of course, I had to root the phone. The LG had only 1.2 Gbytes available for Android, but otherwise the phone is good.

    So, since I develop apps and have built Android ASOP, I decided to use my Linux skills to re-arrange things. It’s conceptually very simple.

    I formatted the SD card as an ext4 filesystem (that’s the Linux filesystem, as opposed to the variation of FAT most SD cards use). I did not encrypt the filesystem, which means I can plug the SD into a Linux machine (or a MAC) and read/update/backup the SD card.

    I let the phone’s built in storage boot Linux (the basis of Android), and use Linux concepts to mount the /data directory from the SD card. This left me with some partitions on the built in storage I can use (recovering about 1Gbyte of higher speed storage), then I use the SD as “/data” which makes the device operate as if it has 32 or 64 Gbytes of “internal” storage.

    It works like a charm, and I’ve used it this way for 2 years.

    There are other benefits and usage options to note:

    Though the SD card is slower, it isn’t usually noticeable in my configuration. With Linux style management of storage I can elect to place things where they work best, and while no consumer would be comfortable doing that, it’s clear to me that could be automated so the user wouldn’t need to know.

    I have a backup (actually several) of the SD card. If (well, when) something crawls in and borks the phone, I can simply pull the backup out of my wallet, swap, reboot….and keep on rolling.

    In my setup I can boot into the “stock” configuration simply by pulling the SD card (maybe replacing it with a stock, blank SD card).

    I only need to root the device to install the configuration. I can remove root (and all root software) once it’s installed, so the phone isn’t rooted during use. Yet, that’s a “customized” phone – I did this to 4.1. If built into the OS, like 6.0 has done, it OUGHT to be better.

    Yet, from what I can tell, the 6.0 implementation is barely ok.

    It will get better, I’m sure.

  8. I just smashed my lollipop device because the move to sd card button wasn’t doing what it said it does.

    How hard is it to make an sd card work properly google?

    I really don’t care about the slightly slower load times on the sd card I just want the extra storage.

    Sounds like they are getting their heads out the bloody sand but i’m honestly not sure if I want to get an android 6 device after my experience.

    I should just make my own cellphone os and show google how its done. Id become a billionaire the night I launched it.

  9. When we see class 10 micro sd cards in the 512gb range…the tradeoffs will be tolerable, methinks.

  10. Brad Linder,

    Thanks for the credit.

    Some clarification on a couple of the points you mentioned:

    Quote:
    After you’ve formatted your microSD card, your phone will treat it as your primary storage space. In fact, if you navigate to the Storage & USB section of your Android Settings, you won’t even see how much internal storage space is available anymore. You’ll only see free space on your microSD card. And if you use a file browser to navigate internal storage, it’ll only show your microSD card — there’s no simple way to copy files to and from the real internal storage.
    End of Quote.

    The only correction there is that the internal storage and SD card, both are visible in Settings – Storage & USB. And you can see the total memory and the used or free memory there. However, if you click Internal, then you won’t see much except the apps there on internal storage. If you click SD card, you will have opportunity to click Explore and that will show SD card in a rudimentary Marshmallow file manager.

    In Internal mode, the Explore button is in the SD card. But if you were in Portable mode, the Explore button would be in the internal storage section.

    In Internal mode, the internal storage is not visible at all in a file manager app, or when you connect phone to laptop (Android File Transfer for Macs) via USB. So you have no ability to micro-manage stuff on the internal storage anymore. All you see is the SD card now.

    In Portable mode, you would see both in a File Manager app.

    The other place you can still see signs of the built-in internal storage, is in Settings – Apps – click on an app that allows move to SD card (some apps do) – click Change Location (not visible if app doesn’t allow move to SD card, and this is also not visible for Portable mode). And using Change Location you can move the app and it’s app data both to either local storage or SD card. So those apps where developer has set the flag in the APK to allow move to SD card – those apps you will be able to move.

    -stereomatch

    1. All in all, it is just confusing for a new user. And the overloading of the “internal” keyword doesn’t help either – SD card becomes “Internal”, yet in settings still the built-in internal storage is “internal”, while SD card is SD card etc.

      The fractured structure that has been constructed cannot be explained in a sentence.

      -stereomatch

      1. Thanks for the clarification! Since I don’t have an Android 6.0 phone with a microSD card slot, I couldn’t test this for myself.

        I’ve updated the post.

        1. Brad Linder,

          There seem to be a few variations also – and bugs in this area. These additional lines from the reddit which I just updated cover those variations – there is a link to screenshot showing movement of app to external SD card which does not allow movement.

          On that poster’s screenshots it is clear he can move the app on his AndroidOne device.

          But I cannot on my AndroidOne device running Marshmallow.

          -stereomatch

          Quote from the reddit SUMMARY section – this section added:

          * The Settings – Storage & USB – Storage – Change location button does not appear if you have Portable mode. That is as with Lollipop, under Portable mode in Marshmallow, you cannot move apps to SD card. However in Internal mode, under Marshmallow, you CAN move apps and app data to external SD card (NOTE: app data is the stuff that gets cleared if you do Clear Data for your app). However, even with Internal mode, you CANNOT move apps which were labelled as non-movable by the developer. For example chat and other apps disallow moving to SD card and these cannot be moved. And system and built-in apps cannot be moved either. **POSSIBLE BUG ON SOME DEVICES:** However, I have seen screenshots (see this post [by Austin Pinto on eyes-free google group] https://groups.google.com/d/msg/eyes-free/rspqjlmu_ss/ouM7TMH-BQAJ, where that device running Marshmallow IS allowing moving all apps (though still excluding system and built-in apps). That is, it is violating the developer’s preference for where the app should be installed. While this seems like a good feature, the downside of this aggressive movement ability seems to be that when you upgrade such an app from Google Play, the updated app will wind up AGAIN on your internal storage, and you will lose your earlier cached data. So for now, only move apps which allow moving, but for users with the variant version of Marshmallow on their AndroidOne device, they will not have any indicator if the app is really allowing movement to SD card, or if it is Marshmallow being aggressive in overriding developer’s preferences.

          * Another **SMALL BUG** that I have seen on my AndroidOne device running Marshmallow is in Settings – Storage & USB – Storage. For an app which disallows Change location to SD card, this does not show the Change location button. But while on this page, if you rotate the phone to landscape mode, the Clear Data became labelled as Change. If you pressed it did nothing i.e. didn’t do Clear Data or do Change. So this is a layout bug in Marshmallow it seems, but it may confuse some users using the device in landscape mode.

  11. We know Google does not want us to use Micro SD cards (otherwise, they wouldn’t have mandated that any manufacturer who wants to make a Nexus device is not allowed to offer a Micro SD card slot).

    So they make it as annoying and inconvenient as possible for anyone who doesn’t root their phone.

    And no, I don’t think its reasonable compromise in any way at all, if you’re deprived of the use of your eMMC. I guess Google engineers will always fail to do what Google doesn’t want them to do. Their job depends on it.

    1. My phone has 4GB total internal storage, and only half (2GB) is available for storing apps. If I can replace that 2GB with 32GB from an SD card, the storage space for apps will be 16 times larger and I will not miss that original 2GB at all. What is unreasonable about Google letting me expand the app storage space from 2GB to 32GB?

      1. My phone has 1.2GB internal storage and was unusable until I used Link2SD to link apps to a partition on the external SD card. Don’t know if that would work for you.

  12. I can see why you need to make the microSD card permanently either internal or external storage… but I don’t understand why you must sacrifice available internal storage in either case.

    1. I can explain that one, though you may find the answer unsatisfactory because ultimately it is possible, but there are net negatives.

      First, think of this as any computer, not specifically a phone or tablet under Android. You have a boot drive, and you add a second drive. Now, you have to elect how to implement that second drive. You have three basic options.

      One, you can move the OS to the new drive (various partitioning/backup software does this for you). This trades storage.

      Two, you can selectively relocate some material, possibly with mounts or links, such that the content appears under a single directory, but is physically divided over multiple drives/partitions.

      The problem with the first method is obvious; you trade storage from one device (presumably smaller) to another one. While Android is based on Linux, it’s built in model of storage is that of a single device. This point makes the second method a similar problem; if you do use links or mounts, only that which appears under the directory /data is considered storage by Android. Everything outside the /data directory is not even considered by Android’s storage metrics.

      The third option is JBOD, just a bunch of drives. It’s one of the RAID options which can format a collection of drives such that they appear as one larger volume of storage. There is a severe penalty here for Android. First, JBOD requires something to assemble this collection BEFORE the OS boots. Usually that’s a RAID BIOS, but conceptually that could be a custom BIOS or UEFI, which is very difficult to arrange on phones at this point. Let’s assume, for the sake of discussion, the device supports it, and you create the volume. This effectively combines storage of the two storage devices, but it bonds them – you can’t pull the SD card out and boot the phone without removing the JBOD arrangement, then reinstalling the OS.

      For reasonable user friendly application, it only makes sense to implement the SD in such a way that if it is removed, the phone still boots and operates. This only works when the SD is a substitute; an alternate which can be removed. This can be done without hardware support, just the rather standard Linux support that’s part of Android.

      The reality is that the internal storage is, in fact, still available for use. It’s just not under Android’s assumed /data directory – it will be in directories which Android considers auxiliary, the way the stock SD card appears. To use it one would have to manually administer links from the SD card’s /data directory into paths available on the internal device, which is an optimization and configuration choice probably beyond the skills of typical users.

  13. Why, I thought they say do no evil? Or do the right thing? Whatever, why MS can treat external storage just fine and when it comes to phone there a problem?

  14. good security practise IMO, for the mass consumer it a good trade off between more internal storage and security.
    It giive choice to budget device user, whom most are tech illiterate, and give them increased security.
    it would be prudent to elaborate the description for the selection thou, for those people who dont understand. also it still need works, like making migration between modes more convenient or multi partition sdcard.
    I mean its linux (in a sense). those feature ald exist for years(ext2sd, swap, etc…), thou not supported by google.

    i hope they use common standard encryption, so there will be work around on other platform to access it

    i just hope internal storage is root mountable too.

  15. This is purely for DRM and copyright issues.

    Secondarily and quite far, for privacy/data-protection issues (in corp environment). If this was the major reason, Google would fix all the other major data/privacy/data-protection huge gaping holes in Android, if it was purely for corporate use needs.

    So, it is for content DRM protection, so that Google can sell more digital consumable from the Play store.

  16. Which file browser was he using that he couldn’t access internal storage?
    Does rooting the phone allow access…or is rooting now dead?

  17. My Huawei y300 had this feature for years, it use the 16gb micro as main and it works realy nice

  18. Seems like a reasonable compromise. If people really need fast loading data, guaranteed, they probably should be buying a more expensive model anyway. For the vast majority of low-end phone users, I don’t see this being an issue. It’s certainly better to have the option to do it than have none at all.

  19. Another possible reason why they aren’t allowing users to use a combination of internal and SD storage, is because of the risk of the user removing the SD card, and ruining the storage volume. If they were combined, some system and app files may be spread across both both physical drives. If the SD card was removed, it could cause major corruption.

    However, it would be really cool if Android allowed users to partition the internal storage, and use a portion of the space (obviously you need the OS files there, in the event you want to revert back to internal storage). If I had a really big SD card, and I assigned it to be my primary storage, it would be cool if I could take advantage of the super-fast eMMC for my camera/videos. I will never use my SD card for taking photos/videos, SD cards arent fast enough. I keep a 64gb SD in my phone, and every few months I migrate over all my photos/videos manually.

    I like that Android 6.0 is offering this flexibility, but I will certainly not be using this feature. I would never give up the faster eMMC drive.

    1. SD cards work just fine for storing pictures and videos. That is because pictures and videos are highly compressed with jpeg or h264 before they go into the SD card. A 1080p HD compressed video stream produces less than 2 megabytes per second of data. On my android phones I have always selected the SD card for storing pictures and videos, and my stand-alone HD video camera uses SD cards for storage.

      1. My contention is that it makes the Camera app more sluggish. I prefer the faster eMMC internal storage. My Class 10 SD card has a write speed around 15MB/s. My Note 4’s internal eMMC has a write speed around 59MB/s.

        There are a few MicroSD UHS U3 cards that can do 60-90 MB/s write speeds, but the Note 4 doesnt support U3 cards (there is a short list of devices that do support U3).

        1. You are right about eMMC being faster than ordinary SD cards. However when you are taking pictures the app only interacts with SD storage for a fraction of a second. At 15MB/s it should take about 0.13 seconds to store a 2MB jpeg image. The biggest delay you see when taking pictures should be from processing (removing noise, correcting colors, red eye removal, scaling, etc) and compressing the image before it is stored.

        2. My G.Skill 64GB Class 10 UHS-1 MicroSD ($22) has around 72MB/s Read and 35MB/s Write. You must have overpaid for a slow microSD ?

        3. I guess I’m just totally ignorant of the write /read speed thing with SD cards, as well as why the migration of a quality SD card and internal phone storage is not 100%. Why does android and google say marshmellow and nougat allows total internal mixing. It hasn’t with marshmellow, and now I have nougat and it still doesn’t. Why do they fool us with the promise of total migration and then it’s still a juggling act moving so many things to the card / internal storage. They are supposed to be as one in my understanding,, right? Thanks

    2. It is not that hard… All you do is keep the partitions separate. Like /system remains untouched but /data gets soft raid 0 to the second /data partition if the raid should fail phone kicks into failsafe mode and factory resets to reset the /data if the SD card fails only thing lost is personal data… But now I know it will be a either or not both situation I will leave it as it is handled normally. 192 gig on my phone…

    3. You have to stop being cheap and get a Samsung micro SD card on Evo Plus or Samsung select and you will have no fails you get what you pay for my micro SD card works perfect for photos videos even 4K and it plays it back perfect

  20. Can’t wait to read about the complaints on the interwebz from the uninformed. Should be good for a few lulz.

  21. Google really can’t seem to wrap their head around storage management.

    But then their whole internal/external split is a game of mental gymnastics all its own.

    When they say external they do not mean external to the device, but external to the OS. Meaning that internal storage is where the OS and app data resides, while external is where anything else resides.

    1. That is pretty obvious. I don’t know how you can ever confuse that..

      1. The point is, why is there the unnecessary possibility of confusion in the first place? The whole matter of storage mis-management is caused by too much control by Google over what the user can and cannot do in terms of installing things.

        1. yeah, the more dominant they are in the market, the less reason to actually serve the customer’s needs… Its the time when ANY business switches over to shenanigans and cosmetic changes to hide the real loss of functionality. Soon, you’ll be as locked in on Android as you are on Crapple’s phones. Unless you root / jailbreak.

      2. I’d expect “Internal” to behave as one HD, whereas “external” would be like connecting an external HD to my computer… it’s not that black and white tho… some apps can’t be installed on the external when formatted as internal… e.g Spotify. I can move my library to the SD if formatted as external, but I can’t have the whole app on the SD if formatted as internal…

        1. Hi,, I’m So disappointed in the supposed ability to use our SD cards as internal storage. You buy 64gb or larger cards, spending possibly dozens of dollars or more, and the find it’s not true added internal storage but a separate entities setup. It’s bullshit that we’re led to believe, oh buy an SD card and alls well, then half info, no info is movable. Then if u truly want more movable info, you have to load yet more storage draining apps to do so. Truly makes no sense.

    2. When people say external what they really mean is removable. The SD card is as internal to the OS as the non-removable memory the phone comes with. It is all block devices, partitions, and file systems to the Linux kernel used by Android.

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