By March 1st, 2012, all applications distributed through the Mac App Store will be required to adhere to Lion’s sandboxing policy. Sandboxing is used to limit the potential damage an application can do by running it in a restricted environment. This means that apps must request explicit permission to perform actions, for example, deleting or modifying files. Since some developers are having a hard time meeting the sandboxing requirements, Apple has delayed the original deadline from November until next year.
The vast majority of Mac users have been free from malware and we’re working on technologies to help keep it that way. As of March 1, 2012 all apps submitted to the Mac App Store must implement sandboxing. Sandboxing your app is a great way to protect systems and users by limiting the resources apps can access and making it more difficult for malicious software to compromise users’ systems. Learn more by visiting the App Sandbox page.
The change will allow Lion to be safer, but it will also neuter powerful apps. We expect that a small number of developers will have to remove their apps from the store completely. Unlike iOS, Mac users will still be able to install 3rd party applications outside of the App Store without any need to jailbreak, so there shouldn’t be any reason to worry just yet—but the move does signal that Apple is looking to further iOS-ify OS X.