RCDefaultApp is a free utility that Creativetechs has started adding to our recommended Mac OS X installs. It adds a special preference pane that allows you to quickly change the default application for many common situations:

  • Open all your .pdf files in Acrobat instead of Preview.
  • Pick a different default mail client or web browser.
  • Control what opens when digital cameras or webcams are plugged in.
  • Close security holes with how certain weblinks are handled.

Of course you can change these settings other ways. But RCDefaultApp makes it much easier by putting the most requested controls into one location — a new “Default Apps” option at the bottom of your Mac OS X System Preferences.


With this plethora of options it can be a little overwhelming for the casual user. We outline a few of the most common examples below.

Open the Default App preference pane.

Once RCDefaultApp is installed, simply go to Mac OS X’s system preferences (found under the Apple menu) and click on the “Default App” at the bottom.

Control which applications open certain files.

Want all your PDF files opened in Acrobat Reader instead of Preview? Want all PDF, JPG, or TIF files to open in Photoshop?

Choose the Extensions tab and scroll down through the list of file extensions to the ones you are interested in. Choose your default application from the pop-up menu.

Tip: Look for similarly named file extensions — especially uppercase vs lowercase. To change your PDF setting for example, you may have to set “PDF” and “pdf” separately.

Pick a different default mail client or web browser.

Do you want to use Entourage as your default email program? Maybe you prefer Firefox over Safari. These settings are grouped together under the Internet tab.

Close security holes with how certain weblinks are handled.

Warning: overly technical content below. Feel free to skip.

Certain of Mac OS X’s default handlers for custom URI protocols (weblinks) expose exploitable security holes. One such vulnerability is detailed far too thoroughly at the special Month of Apple Bugs website.

These types of vulnerabilities can be addressed by choosing the URI tab and setting any vulnerable URI entries to “disabled.”

For best security, we’d recommend disabling the following URI:

  • rtsp (vulnerability described here)

For additional details we’d refer readers to the article Disabling Unsafe URI Handlers With RCDefaultApp at Daring Fireball.

As our security-conscious consultant Jordan Bojar said when lobbying for the addition of these security details, “Mostly, it’s just cool to set all your PDFs to open in Acrobat.”

Source: This tip inspired by research and testing by Creativetechs consultant Jordan Bojar.