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My phone (Sony E4g, running Android 4.4.4) offers the possibility of moving some of the installed apps partially onto the (removable) SD-card. I use this feature regularly, and -in theory- quite a big part of the apps are already moved on it. My problem is however that I can't find these anywhere on the SD-card, and there are no separate partitions on the card either. So my question is: where exactly are this moved apps stored on the external storage in KitKat ? Thanks.

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OK, after some research it seems that all the apps moved to external SD-card are in the virtual file system /mnt/asec, which is, in turn, an abstraction layer over the encrypted files stored in the hidden .android_secure folder, on the ext. SD-card.

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Generally, you cannot see app data files on internal storage unless you have root - I would assume that this is the same with data files on external storage. A quick check with one of my apps shows me that even after moving it to the SD card, the data is still in /data/data, without a symbolic link or anything. Of course, this doesn't mean that the files aren't on the SD card - maybe the Android system itself just "sees" the files as on internal storage but really they're on the external one. There also doesn't seem to be anything in the /storage/sdcard1/Android/data/app.package.name (or /external_sd/Android/data/app.package.name) folders, however that's where I would assume they're stored. I see your point though, and I would like to know myself exactly where they're stored - but I can't exactly fit this all into a comment. Some apps use root and a second partition to completely move app data and create "links" (specifically symbolic links) between where the actual files, libraries, APK files etc. are stored and where they normally would be. This is done on a second partition as there is a large risk that the first partition will become unmounted when you plug your device into a computer in MTP (Media Transfer Protocol) mode, and if it was unmounted it would render a large amount of apps useless.

When you've got a large amount of apps moved onto external storage, make sure that the microSD card is always plugged in and that you don't delete anything off it. You can run into issues such as the whole app being unavailable and yet still taking up space on internal storage if this happens.

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    Thanks for the answer. My phone actually restarts as soon as I try to unmount the external SD-card (in the settings menu). One remark to your answer: connecting in MTP mode does not result unmounting any partition. – zrx8 Oct 31 '15 at 8:59
  • Really? Link2SD states in its description that Android unmounts the first partition when you connect your device to a PC ad mass storage. I assume that's MTP... – Joe Oct 31 '15 at 9:35
  • Oh yeah, your answer seems right. It makes sense that they're stored there – Joe Oct 31 '15 at 9:38
  • No, MTP is not mass storage. The problem you describe was a big reason for Android to change from using mass storage to MTP. See android.stackexchange.com/a/56094/12442 for more details. – Dan Hulme Jan 8 '17 at 12:29

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