Unable to open any downloads on Macs?

Some Macs may have what is called "Gatekeeper" enabled.  If so, you may find when downloading software, your mac does not allow you to open and run downloads.  You run into errors every time.  You may also try one from the app store, which does work. 

Here is how to fix it.

Step 1: Open Terminal quickly by pressing Command Space and then find Terminal.

Step 2: Type in the Terminal command line below to request disable Gatekeeper on Mac.

sudo spctl --master-disable

Step 3: Enter the user password on your Macbook. Note that it will not display the password when you enter it. Just enter it and press Enter.

If you enter the wrong password, you will be told Sorry, try again. Just re-enter the correct password and press Enter.

Step 4: Check if Gatekeeper has been disabled successfully by typing the command below and pressing Enter.

spctl --status

Step 5: It should be disabled now.  You can check by opening Security & privacy, look at the General tab, make sure it says can open from anywhere.  Try to open your download again.

(source: https://lucidgen.com/en/how-to-disable-gatekeeper-sip-on-mac/)