12 answers
This is how I installed the Sentinel software:
The newest Mac OS has removed the "Allow From Anywhere" option from the "Allow apps downloaded from:" section under Security & Privacy
After you try to install the software you will get this warning. Hit OK and then go to the "Allow apps downloaded from:" section under Security & Privacy.
I had the Security & Privacy screen open already, which may help.
Then it will give you the option to 'Open Anyway' for the Sentinel.pkg
Hope this is helpful.