How to copy Sandbox back to Macintosh HD?

[dnanian]

Yep -- I consciously made the details a bit sparse to encourage discussion and contact. Looks like it worked!

The key here is to ensure that you haven't "manually" made any kind of alias from the original volume (which I'll call Macintosh HD) to the Sandbox. As long as you haven't done that, you can clone back to the original. Note, though, that this is a pretty advanced operation, and I seriously suggest that you have a current backup of your original drive before you try this.

Use "Backup - all files" and then use Smart Update as the copy type. Then, sure, you can boot again from Macintosh HD to check it out. It should be running the new OS.

If you're in a situation where you've made very few changes, I still advise you to do it the "regular" way -- namely, boot to the original, install the updates, update the Safety Clone, and boot back to it. But this does work, and can be very convenient.