According to complaints on Apple’s support forums，Some 2018 MacBook Pro users who try to upgrade to the macOS Mojave encounter errors that prevent them from completing the process.
A common factor appears to be Apple’s T2 chip, so far found only in the iMac Pro and 2018 MacBook Pro. This not only runs the SMC, Touch Bar, and Touch ID, but includes an image signal processor and controllers for audio and mass storage.
Users are encountering messages like “An error occurred installing macOS,” or cryptic references to bridgeOS, the modified version of watchOS used to handle Mac subsystems like the Touch Bar. There is no one-size-fits-all solution, though some people have managed to get around the issue by resetting their Mac’s system management controller, or SMC. Even then, users may encounter glitches and strange errors.