When a program is installed in OS X, the system will scan it for various capabilities, including what document formats it can handle, and then will make the program available as an option for managing these formats and other functions. While this is commonly used for document formats, it is also used for URL links, such as those for Web pages, FTP sites, media streams, and E-mail.

For any content type, be it a file, URL, or anything else, OS X will have one program be the default handler that will open to manage the content, unless another program is specified. For files, this can be done by right-clicking a file, or selecting it and going to the File menu, where you will see an “Open With” submenu that contains the programs capable of managing that file in one way or another.

While the Open With menus provide some level of convenience, if you would like to always have a document or set of documents open with a specific program, then you can do so by two approaches: Document-specific settings, and global settings.

Document-Specific settings

The services in OS X that associate documents with programs do so on a global basis; however, OS X supports an option for a single file to override these settings and be always opened with a program of your choosing:

1. Right-click the document and choose “Get Info,” or select it and press Command-i
2. Expand the “Open With” section of the information window
3. Choose a desired program from the drop-down menu.

A second approach to this is to hold the Option key when right-clicking or choosing Open With from the File menu, where the menu name will change to “Always Open With,” and selecting a program will make this association for this document.

While the basic use of this is described for one document, you can also do this for multiple documents by Shift- or Command- clicking them to add them to a selection, and then right-click or use the File menu to act on the entire selection. Note that getting info on small selections will show separate Info windows for them; however, you can hold the Option key when getting info (i.e., press Option-Command-i) to reveal the inspector that will show common information on all of the selected items.

Global settings

If you decide you want all files of a specific type to open with your preferred program, then you can do so by simply getting information on one of the files and following the steps above to view the file’s information window. From here, once you select your program from the drop-down menu, clicking the “Change All” button will have the system change the global settings to handle your document.

Once this is done, you should see the icon of all documents of this type change to represent the program you have chosen; however, this may require you log out and back into your Mac before this takes effect.

Troubleshooting

While the above steps should have OS X associate documents with different programs, sometimes you might run into troubles, the most common of which are your desired program not showing up in the Open With menu, or your settings not sticking in one way or another.

For programs not showing up in the Open With menu, keep in mind that OS X only scans the capabilities of programs in default locations like the Applications folder, so be sure you keep your programs in there if possible. If not, then an alternative is to create a folder called Applications directly in your home directory and store the programs in there (OS X should similarly scan this folder). While these are recommendations, you can technically store programs anywhere you want, and when you open them, OS X should read their capabilities.

A final issue is if you are using a program where the developer has not properly listed the documents it is capable of opening, so OS X has no way of making this association. In these and all other cases where programs do not show up in the Open With menus, you can choose the “Other” option in these menus and then browse the Finder for your program (note you might have to select “All Applications” from the Enable menu at the bottom of the Open dialogue box to select the one you desire).

For any time your settings do not stick, then you will need to look into resetting your Mac’s launch services, which is the background service that OS X uses for making these associations. To do this, you can use any of a number of cleaning or “maintenance” utilities to specifically run a “rebuild launch services database” (or similar) option, or you can use the OS X Terminal to run the following command (copy all lines together, including terminating slashes, and paste them into the Terminal before pressing Enter to run them):

/System/Library/Frameworks/CoreServices.frame\
work/Versions/A/Frameworks/LaunchServices.fra\
mework/Versions/A/Support/lsregister -kill -seed