Please help! I’m a web designer, and I just upgraded to Snow Leopard. As soon as I did that, everything went awry. Text files that I created in BBEdit are now opening in TextEdit, HTML files that I created with Dreamweaver are now opening in Safari, JPG images that I created with Photoshop are now opening in Preview, and PDF files that I created in Acrobat Pro are opening in Preview! What in the world is going on here?
We’ve got multiple solutions for your problem, but to understand what’s happening, let’s take a brief walk down history lane. In the past, your Mac has always opened your documents based on their “creator code,” an invisible code embedded into each file that tells your Mac which application created that file. For example, if you created a JPG file using Photoshop, that JPG file would always reopen in Photoshop. But if you created another JPG file with Illustrator, that JPG file would always reopen in Illustrator.
However, starting with Snow Leopard, the creator code is now ignored by the OS in favor of the file extension. This means your Mac acts a lot more like a Windows PC because a file’s extension dictates which application will open it. So in Snow Leopard, all JPG files will now open by default in Preview, regardless of which program created them.
Magic Launch understands creator codes and lets you set other rules for launching files as well.
You can override this behavior on a case-by-case basis by manually dragging-and-dropping a file onto any application that can open that type of file. You can also set a file’s opening application by selecting your file in the Finder, choosing File > Get Info and choosing an application for “Open With.” If you click the “Change All” button, that will change the default opening application for every file with that extension.
But who wants to go through extra steps when this whole process used to be so easy? Fortunately, a System Preferences pane called Magic Launch ($14, michelf.com/software/magic-launch/) lets you re-enable creator codes in Snow Leopard. Even better, Magic Launch gives you new functionality that you’ve never had before. Similar to the rules that you can create in Apple Mail, Magic Launch lets you create rules to determine which application should open which documents, based on criteria such as file location, file name, or text contents. So, for example, you could put all of your BBEdit text documents into one folder and those will always open up in BBEdit, regardless of any other application settings on your Mac.