Clearing the quarantine extended attribute from downloaded applications – macOS

When I’m packaging an application for deployment, I normally download the latest version from the vendor. If it’s a drag-and-drop install, where the application is a self-contained bundle, it will get the com.apple.quarantine extended attribute associated with it.

The quarantine attribute is added by the OS so that it can ask for user confirmation the first time the downloaded program is run. Gatekeeper in Lion and Mountain Lion also uses the com.apple.quarantine attribute to determine if an application should be checked (and blocked if needed.)

To avoid issues with both unwanted messages and Gatekeeper, I normally clear this attribute as part of my packaging. Here’s how to check to see if your application has the com.apple.quarantine attribute associated with it:

1. Open Terminal
2. Run the following command:

xattr /path/to/MyApp.app

If the com.apple.quarantine attribute is associated with the application, you should see the following output:

xattr /path/to/MyApp.app
com.apple.quarantine

Note: Other attributes may also be listed, with com.apple.FinderInfo being a common one.
To remove the quarantine attribute, you would then run the following command:

sudo xattr -r -d com.apple.quarantine /path/to/MyApp.app

That will recursively remove the com.apple.quarantine attribute from the application. The -r option will allow the quarantine attribute of all files inside the application to be selected, while the -d option causes the given attribute name (and associated value) to be removed.

How to speed up Time Machine so it backs up your data faster – macOS

If you are a constant-on Time Machine user, you won’t even notice when a scheduled backup is taking place. That’s because Time Machine is designed to work quietly and slowly in the background. Most of your regular backups are incremental and therefore don’t need much power. If you only back up your Mac once per week (or longer), Time Machine has a lot more work to do, but still runs quietly and slowly in the background. Using this Terminal command, you will disable the disk operation throttling so Time Machine will run faster.

sudo sysctl debug.lowpri\_throttle_enabled=0

Restore default setup:

sudo sysctl debug.lowpri\_throttle_enabled=1