[Q] Can't Encrypt Galaxy SIII i9300

Hey,

I'm having trouble encrypting my i9300 device (I need to encrypt my device for work's email)
I've set a good password, and my device is at 100% battery.
Whenever I've tried to encrypt it, it got stuck with the green robot and it seems it doesn't do anything.
I'd even stayed my phone for the night with that green robot, and nothing happened.
I can reboot it, and everything is back to normal... but no encryption.
I've tried to replace my ROM to Stock ROM, and CyanogenMod, and it's the same.
I'm now with Android Revolution HD 22.4.
I've tried to locate errors with adb and logcat, but haven't seen anything that is relevant to the encryption.
Anyone here got the same problem or knows how to fix it?

Thanks,
Adam