How to use DoubleTwist Sync with Android Marshmallow adoptable storage I have a Samsung S7 for which I bought a 200GB microSD card.  I formatted it as adoptable storage (using an adb shell workaround because Samsung has actually disabled the Marshmallow feature by default).  Now, I can store all manner of things on it, including about 17GB of music which I manually copied over.

However, I want to use DoubleTwist Sync as I have lots of iTunes playlists that don't get copied over when manually copying files.  I installed both the DoubleTwist PC app as well as the Android app but when I tried to sync, it just tells me that the device is out of space.  I know that this isn't technically true as it's a brand new card and I just copied over 17GB of files.  In fact, when I deleted the 17GB, it still told me that there's no space.  I'm sure the problem is that DoubleTwist can only see a limited partition and it is somehow confused by adoptable storage.

There's an article on their site (https://www.doubletwist.com/help/question/how-do-i-switch-from-internal-storage-to-sd-card/) describing how to switch from internal to SD storage, but I think it was written without adoptable storage in mind, as my Settings doesn't have the "Storage" option they refer to.

Any ideas on how I can fix this?  My last resort is to re-format the card as 50% adoptable storage partition and 50% portable storage partition.  To be honest, I probably should've done this from the get go but I'm hoping there is a quicker solution that doesn't involve reformatting.
Ok, I figured it out.  It wasn't some fundamental problem with how adoptable storage works, I just didn't do it right.  After setting up the SD card as adoptable storage, there is one more step which is not made clear by most tutorials.  You need to select the card and in the Options, select "Migrate Data" which completes the process and makes the card available for use by other apps, or something like that.