“This Program can’t be opened because it is from an unidentified developer”
Apple are getting tighter on which software they allow you to run on your computer. This is good because it avoids you getting any malware on your computer from bad software developers. But it also means that some legitimate software won’t run. If you are trying to download software from somewhere other than the Apple app store and you trust the source you are downloading your software from, here’s how to manually turn on the security settings for it to run.
This is what the error looks like.
You need to go to system preferences from your Apple menu and then select “security and privacy.”
Down in the bottom left of the window there is a little lock that you will need to select.
Now you can see a message telling you that the software you were trying to run was blocked and you can click “Open Anyway” to allow the software to run on your computer.
You only need to do this the first time you run the new software. OS X will remember it from then on and run the software without giving you the error message.