Topics | Info window
Types and creators
In Mac OS X, the rules governing which application will be used to open a file based on the file's type, creator, and extension are somewhat complex, but file creators are a common way for Mac OS X to determine which application should be used to open a file. File types can also be used to determine which application will open a file, as well as indicate to an application the nature of the data in a file.
Changing types and creators
To change a file type or creator, use any of the following options:

- To assign a new file type, type the new 4-character code into the Type: field. File Buddy will attempt to complete the type based on types assigned to other files in the past.
- To assign a new creator, type the new 4-character code into the Creator: field. File Buddy will attempt to complete the creator based on creators assigned to other files in the past.
- Choose the appropriate command from the Use same: pop-up menu button to use the same type and/or creator code as an existing file.
- Choose a previously used type from the pop-up menu next to the Type: field. This menu remembers file types previously assigned using an Info window, and is sorted by frequency of use. The more often you assign a type, the closer it appears to the top of the menu.
- Choose a previously used creator from the pop-up menu next to the Creator: field. This menu remembers creators previously assigned using an Info window, and is sorted by frequency of use. The more often you assign a creator, the closer it appears to the top of the menu.
- Drag a file with a type you wish to use into the Type: field.
- Drag a creator with a type you wish to use into the Creator: field.
- Drag a file with both type and creator you wish to use into the space between the Type: and Creator: fields to copy both.

File types and creators always contain exactly four characters. Some file types such as ‘PDF ’ may appear to have fewer than four characters, in which case one or more of the characters is either a space or a non-printing character. File Buddy interprets an empty field as equivalent to four null characters, in which case the file is said usually said to have no creator or no file type.
Files with no type or creator
Some applications in Mac OS X do not assign type or creator codes to files, as they are no longer strictly required if the file has an extension. Such files will not work in Mac OS 9. The Info window has options to suggest type and/or creator codes for files which do not have them if the file has a recognized extension. Use the Info window preferences window to enable or disable these options.
Removing custom menu items Info window preferences