ERROR - "SOL" CAN'T BE OPENED BECAUSE IT WAS NOT DOWNLOADED FROM THE APP STORE.

Go to System Preferences (up in the right hand corner you can click on the looking glass and type System Preferences if you aren't familiar with macOS)

Click on System Security & Privacy

In the bottom left click on the lock and type the computer password and UNLOCK

Change the radio button to "App Store and identified developers" and then run the install again. Here is the link (or if it is already downloaded) - Install the SOL Software for macOS: Click Here