How to decrypt an undecryptable micro SD card?

Question

I encrypted my micro SD card and used it (and encrypted/decrypted it) without issue during some months. But one day, without explanation, my micro SD card is no more decryptable: the encrypt screen at Android startup (or SD card inserting) is loading unending or showing "0Mb/0Mb - 100%" and micro SD card still unavailable and invisible.

When I connect the SD card directly to PC or Mac, files tree is browsable, files are visible but unreadable.

I tried some softwares like Android File Transfer or Android Data Recovery (Wondershare Dr.Fone for Android), without success.

I don't want to reset my phone because I will lose all my micro SD card data. Is there a way to recover data from corrupted and undecryptable micro SD card?

• Phone : Samsung Galaxy 7 (SM-G930F)
• Android : Marshmallow 6.0.1

Answer 1

I finally find a solution in an recovery-android.com comment by vid971 :

1. Go to Lock Screen and Security and select None and Keep Fingerprints. You will then be asked for setting up a password.

2. Remove the SD Card from the phone and Reboot.

3. When phone has rebooted put your SD Card back in. You will have windows prompts, for you Sim card Pin and Mobile Data usage, and after that you'll be on the Encrypt SD Card page. Click Encrypt. As your card is already encrypted it will be fast.

From then your SD Card should be recognised again and usable.