The full message you might see is the following:
“OfficePool 2017” can’t be opened because it is from an unidentified developer.
Your security preferences allow installation of only apps from the Mac App Store and identified developers.
To override your security settings and open the app anyway:
- In the Finder, locate the app you want to open. (Don’t use Launchpad to do this. Launchpad doesn’t allow you to access the shortcut menu.)
- Press the Control key and click the app icon, then choose Open from the shortcut menu.
- Click Open.
The app is saved as an exception to your security settings, and you can open it in the future by double-clicking it just as you can any registered app.
Note: Another way to grant an exception for a blocked app is to click the “Open Anyway” button on the Security pane of System Preferences. This button is available for about an hour after you try to open the app.
To open this pane, choose Apple menu > System Preferences, then click Security & Privacy.