After removing data back from sd card, my data disappeared!

[Android Central Question]

So, I am using Android 6.0. My phone has the ability to have two sim cards or one sim card and a sd card at the same time, because i rarely use the second sim card, I took it out and replaced it with a newly bought sd card. I adopted it as internal storage, my data was moved properly and there was no problem.

But I still want to use the second sim card from time to time, and as an adopted sdcard it is too inconvenient to remove in this case, so i decided to change it back to portable sd card.

First, I moved back my app. Then I went to internal storage (original phone storage) and chose "migrate data". When all data was moved successfully, my phone storage was back with nearly 2 GB unused, and the sd card gone from 13 GB used to 100+MB used. I didn't know what those 100+ MB data were (the card said that, but it was empty and I couldn't find anything in it), but since all the data I needed were backed to phone storage again, I thought that wasn't important, right?

So I formated the sd card to portable card, when the process was done and the sd card was back to being portable, there was a sign appeared saying an android media something wasn't working right... Then I went to the phone storage to check, all my media data was gone! It still showed the media data amount (more than 8GB), but when clicked in, nothing was there! And I could not use my camera, or any other app that required picture saving either...

I was really panic, so I decided to change the sd card back to internal storage. Since it was empty already, I left the data untouched and just formated it. I now can use my camera and the app related, but the media data from earlier still disappeared! The card still showed 8 GB media data, but when clicked in, it was totally empty! I went to gallery and there was nothing either.

I can't understand what did I do wrong, where did my media data go? Why does my phone and card say like my data was still there but i can't see it? Why does my camera doesn't work when the sd card back to portable? How can I remove the card but not let it affect my camera? Please help!

 

[Rukbat]

You're not going to see anything on the "external" sd card when it's formatted as internal, because there is no external card. The card is mounted as part of internal storage.

As far as what happened to the data, I'd have to have the phone in my hands to be sure, but I think that "migrate data" migrated your data TO the card, not from it, and then you formatted the card, deleting all the data that had been moved to it.

If you want to use the card without the SD card, format the sd card as external, then set the camera to save on the sd card. Then change it back to save on internal storage. (Evidently the camera app made a folder to store pictures in on the card when it was mounted as internal storage - and couldn't find it when the card wasn't there any more.)