macospermissionSecurity
I'm getting this error trying to install software on MacOS Sierra (10.12.5):
Your security preferences allow installation of only apps from the App Store and identified developers.
I'd like to change the settings so that these types of installations are allowed. Similar to what is shown here:
However, my system doesn't seem to have the Anywhere option (screen shot below). This option is also not available if the Advanced button is selected.
Solved the problem! The quarantine metadata was not clearing correctly for some reason. I fixed this by doing:
sudo xattr -d com.apple.quarantine /Applications/Coda\ 2.app
Big thanks to Thomas Reed in the Apple discussion forums - Link to answer.
A feature of OS X Mountain Lion is the ability to run only signed applications - that is, applications from Apple's app store - out of the box. This is a configurable setting, however, and can be changed in the settings screen you seem to have already uncovered. If you set the "Allow applications downloaded from" option to "Anywhere", your Mac should run applications downloaded from the internet as well.
Do be aware of the security implications of this, and consider changing it only when necessary (and reverting the setting after you've installed the downloaded application which you trust).
For more information, and screen shots, see: http://www.maclife.com/article/howtos/how_tweak_settings_gatekeeper_mountain_lion
Best Answer
From: How to Allow Apps from Anywhere in macOS Sierra Gatekeeper