So many people like to ask "Did you do a clean install?" when someone has a problem with iOS7. But I'd like to know: What IS a "clean install"? According to Apple the correct procedure for upgrading major versions of iOS is: 1. Back up key elements of your device, such as settings, Contacts, Calendars, Notes, and your Camera Roll. 2. Update your device to the latest version of iOS software. 3. Restore your device from your most recent backup. 4. Restart your device. (Actually done automatically.) 5. Sync back media content from your iTunes Library to your device. This is the only way I know of installing the GM. What's the other way? The "clean install" way?