It really is a nuissance. You get used to the look and feel and sound (!) of a system. Basically, the OS looks very much the same after the update but the different volume changing sound is a bit unnerving. Unfortunately, you cannot just copy the old file into the place the system is using for storing the sound. Reason is the so-called “System Integrity Protection,” which takes away the rights of administrators to fiddle with the internal organs of their own system. This seems to be a good idea to protect you against malware. However, in me it creates an uneasy feeling. After all, I’ve paid for the computer. It’s mine. How dare the system hinder me from editing it? This is the workaround:
- Disable SIP: 1) Reboot into recovery OS (you gotta press cmd + R upon start); 2) start terminal (in Utilities); 3) type in “csrutil disable” (without the quotation marks) and hit enter; 4) reboot your computer.
- Copy the old sound file into the position of the new one. (By the way: Create a backup of the new file, if you want to keep it. You can always copy from the system folder into another folder using Finder.): 1) start terminal; 2) “cd /System/Library/LoginPlugins/BezelServices.loginPlugin/Contents/Resources”; 3) “sudo cp “***” volume.aiff” (*** is the path to the old sound file you want to copy into the system folder / you can drag and drop the address from the bottom of your finder window if you select the file in there).
- Enable SIP: 1) see above, but this time type “csrutil enable”; 2) reboot the computer; 3) Robert is your father’s brother.
PS: Just read here that SIP can cause other issues, too…