The classic startup chime has been disabled on newer macs, Late 2016 and on, but it’s not gone and it’s possible to enable it again. Another new feature is automatic boot-up when the lid is opened, which can also be disabled.
To return to the old settings, you have to open Terminal in /Applications/Utilities/ and run two commands.
Here is the command for enabling the startup sound again:
And here is the command for disabling auto-boot:
After running this, you will have returned to the old settings, however, it is not a permanent change. It is stored in the NVRAM which might be reset every once in a while. There is a solution if you want this to be permanent.
First, open Script Editor in /Applications/Utilities/ and paste this into the document:
do shell script "nvram BootAudio=%01" with administrator privileges
do shell script "nvram AutoBoot=%00" with administrator privileges
Save it as an application wherever you like. Then open System Preferences, search for “Login Items”, open the panel, click the plus under the list of startup applications, navigate to the application that you just created and select it.
Every time you login, the application will automatically launch, enable the startup sound and disable auto-boot, but it will prompt you for your password every time you login. If you want to fix this, you have to edit the
/etc/sudoers file. Do not open the file directly, instead run
sudo visudo in Terminal. Then add this to the end of the file:
username ALL= NOPASSWD: /usr/sbin/nvram BootAudio=%01
username ALL= NOPASSWD: /usr/sbin/nvram AutoBoot=%00
This will enable you to run these two commands without having to type in your password. Every time you login, the application will automatically launch, enable the startup sound and disable auto-boot.