[header] How to open idx files [title] Double-click on the idx file. [step] The file will automatically open in notepad on windows, or in textedit on mac os x. [substeps] If the idx file fails to open, proceed to the next step. [title] Right-click on the idx file, and select " open with. 
[substeps] If using mac os x, select " get info, " then click on " open with. " [title] Select any text editing program installed on your computer.