I encrypted my phone. That worked fine. Then I installed another version of Cyanogenmod. This cannot decrypt the data (which is OK: There is no important data on the phone). It tells me to perform a factory reset, but even after the factory reset the phone is stuck at the "Encryption unsuccessful".

The error I get is the same as on: Samsung Galaxy encryption failed

How do I convince Cyanogenmod that all encrypted data is deleted?

I have tried:

  • Factory reset
  • Installing the version of Cyanogenmod that encrypted the phone

3 Answers 3


The factory reset failed to format /data (and thus most likely left the old encryption in place).

Having formatted /data manually, the factory reset finally could complete successfully, and the new version of Cyanogenmod showed up.

  • 1
    @Downvoters: This perfectly makes sense to me, so I re-phrased it to make it easier to grasp: it could well be that CM did not know the "old" encryption key, and thus was unable to access the (existing) file system. Formatting the partition created a "virgin" file system without encryption, and thus made it accessible again (to my understanding).
    – Izzy
    Commented Mar 13, 2014 at 15:54

You have to enter recovery mode, (mine is TWRP 2.8.1), than from recovery change data system type to etx4.


Format sdcard0 (internal storage) to ext3 file-system format and it is going to be OK!

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .