Note: This guide is geared toward the Samsung Captivate. If you have a different device, try your device's forum, or search my thread on XDA about this.Are you using ICS and pulled your phone out of your pocket only to find that it had this screen, saying "Encryption unsuccessful" and your only option a button that said "Reset Phone"? Don't press it! Try rebooting a few times with your external sdcard out first. Sometimes that will fix the issue. If not, take a deep breath and follow the guide to get your phone usable again: