Apple Certified Support Professional (ACSP) Practice Exam

Creating a new login keychain results in a fresh start for storing authentication information, which means that it does not inherit any existing saved passwords or authentication secrets. The new login keychain initializes as empty, effectively resulting in the loss of access to all previously stored items in the previous keychain. Users would have to re-enter passwords and information that they require as they will no longer be accessible from the newly created keychain.

The other options don't accurately describe what happens with the creation of a new login keychain. For instance, backing up existing keychains is not a feature of the process; it simply initializes a new one. While creating a keychain can be part of enhancing security practices, the immediate consequence is the emptiness of the keychain. Also, the new keychain does not automatically synchronize with iCloud unless specifically set up as such, and this action does not directly enhance security layers.