Aggregate Audio Device settings will not save on restart fix in OSX :
If you have more than one user account, you must be logged in as an administrator to carry out these instructions.
Triple-click anywhere in the line below to select it:
sudo chown 202:202 /L*/P*/A*/*.audio.*.plist; sudo chmod -N $_
Copy the selected text to the Clipboard (command-C).
Launch the Terminal application.
Paste into the Terminal window (command-V). You’ll be prompted for your login password, which won’t be displayed when you type it. If you don’t have a login password, you’ll need to set one before you can run the command. You may get a one-time warning not to screw up. Confirm. You don’t need to post the warning. If you see a message that your username “is not in the sudoers file,” then you’re not logged in as an administrator.
Quit Terminal and reboot.
To test if it worked create an aggregate device in audio midi setup, restart your mac and check that your new device settings saved.
Model Name: MacBook Pro
Model Identifier: MacBookPro11,5
Processor Name: Intel Core i7
Processor Speed: 2.8 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Memory: 16 GB
Boot ROM Version: MBP114.0172.B07
SMC Version (system): 2.30f2