Hey, folks.

As you may know, one of Mojave's focuses is stability and security. Part of that is denying applications, including those with 'root' privileges, the ability to access certain files on the drive.

This started in High Sierra's SIP implementation, where certain system files were inaccessible. But Mojave extends this protection to "sensitive" user files as well.

As you might expect, not being able to copy files throws a bit of a wrench into the whole "backing up" process, and bad things happened when we tried (crashes, etc).

Fortunately, as of Public Beta 2, you can now tell Mojave that SuperDuper is a "good actor", and you should allow us to access your data. Mojave doesn't prompt you to "OK" us, however, so you need to do this before you run.

Open System Preferences and switch to the Security & Privacy preference pane. Under Privacy > Application Data (Full Disk Access in later builds), add SuperDuper.

Once that's done, your backup should work.