If you are encountering issues while trying to upgrade your MacBook Pro to macOS Mojave, then you are not alone. Many MacBook Pro users have taken it to Apple Support forums to discuss the issues they are facing during the installation process. Many users report getting the “An error occurred installing macOS” error. Others are also reporting error messages related to the bridgeOS, which is a modified version of watchOS responsible for features like the Touch Bar.
An issue that is at the center of this problem appears to be related to Apple T2 Chip notes AppleInsider. This new chip is found on limited models of Macs including the 2018 MacBook Pros and iMac Pro. The T2 chip is responsible for the Touch Bar, Touch ID and SMC along with the image signal processor and controllers for mass storage and audio. Many users are reporting that resetting their Mac’s System Management Controller or SMC helped them in successfully finishing the macOS Mojave installation process. Although doing so isn’t resulting in solving the issue for all users, who continue to get errors.
While Apple has not provided any support document that can be helpful in this specific matter, some users on the support forums say Apple has acknowledged the issue and might release a fix in the near future.
Until then it is advisable for those who are upgrading to macOS Mojave to backup their data before starting the installation process.