After Downloading and Installing ARES Commander 2019 from Google chrome or Mozilla firefox, if you get the following error message "ARES Commander 2019 " can't be opened because it is from unidentified developer" on start up of ARES Commander 2019 then you have to set the following Security and Privacy settings on your Mac system.
Go to System Preferences -> Security and Privacy -> General tab > Allow apps download from:
2. Please click on "Lock icon" which at bottom left side and enter your Mac system password if any.
3. You will see options now become activated and notification message appeared "ARES Commander was blocked from opening.." under App Store and identified developers option.
4. Please click on "Open Anyway" button.
5. You will see a dialog box where Verifying "ARES Commander " process is starting.
6. After completion of this process ARES Commander will start successfully.
7. Close Security and Privacy dialog box.