Pick Tools > File Formats 
to see and manage the entire list of file formats.
The order of the list is important. When Beyond Compare looks for a file format to use on a file, it scans this list from top to bottom, stopping on the first enabled item whose mask matches the filename. To change the order of the list, highlight an item and click the Move Up 
or Move Down 
button. To enable or disable an item, mark or unmark its checkbox.
An item is colored red if any filename it could match is already matched by an item higher in the list. A disabled item is colored gray. An item with an empty mask cannot match any filename. To use any of these file formats, you must manually pick them in file sessions.
Note A specific session can independently enable or disable file formats. (See Folder Compare Miscellaneous Settings.) This way you can have a special file format that is used only by one session.
See also