1. Open System Preferences.
2. Click on Security & Privacy.
3. Make sure that the General tab is selected, and then click on the lock icon to make changes.
4. If prompted, enter your computer password to continue unlocking.
5. Select to allow apps to be downloaded from Anywhere.
6. At the security prompt, click on Allow From Anywhere.
7. Click on the lock icon again to lock the changes in.
8. Close out of System Preferences.