Give your Mac permission to open new apps

File and app permissions can complicate your Mac life greatly. Have you ever received an error message that tells you you’re unable to open an application because it wasn’t downloaded from the Mac App Store? That’s because OS X has a feature called Gatekeeper that won’t let you open such apps.

Gatekeeper is part of OS X’s built-in anti-malware checking system, to prevent you from being exposed to online hackers or those who want to gain access to your computer for nefarious purposes.

Gatekeeper basically checks apps for recognised Apple developer ID signatures to make sure that they are indeed from whom they’re supposed to be, and to prevent hacker types from disguising malware as the apps you might want to use. By working with an ID program, developers are able to release software for the Mac on services other than the Mac App Store that will still run without problems – though you do have to let Gate-Keeper know that it's okay. 1 How to change Gatekeeper's default settings Open the Security & Privacy system preference. Click the lock to make changes. Then you can change the ‘Allow apps downloaded from’ setting to whatever suits you – if you want to live dangerously, pick ‘Anywhere’.

2 How to exempt Gatekeeper from keeping an individual app from opening If you’re confident an app you’ve downloaded is safe, right-click on its icon in the Finder and click Open. Gatekeeper will warn you that the app is from an unidentified developer; click the Open button to continue.

3 What to do if Gatekeeper tells you the app you’re trying to open is damaged If you get a warning saying that the app you’re trying to open is damaged, trash it immediately. It means that it’s been altered by someone other than the developer. That can happen by accident, but it can also indicate a malware spoof – it’s better to be safe than sorry.