Even if you forget the password of the encrypted MacBook Pro, you can still reinstall macOS on it by erasing the drive. Given that you have created a backup for your Mac, you can restore your files from the backup after reinstalling macOS.
To reinstall macOS on your encrypted Mac drive, you must decrypt it with the password. If you forget, you can only erase the drive to continue reinstalling macOS. Although erasing the drive deletes everything, you can restore files Time Machine backup, or other backups.
- Boot Mac into macOS Recovery Mode.
- Select Disk Utility, choose your Mac drive, and click Erase.
- Back to the macOS Utilities screen and select Reinstall macOS.
- Open the download dmg and select the erased drive.
- Click Continue and follow the onscreen guide to complete the process.