Think of it like the index at the back of a textbook. The textbook's content (the actual data) is one file, and the index (the .idx file) tells the software exactly where to find specific terms without scanning every page.
Only keep .idx files that came with a video file ( .avi , .mkv ) or a DVD folder you created yourself. Delete any .idx file that appears alone in an email or download. what is .idx extension
The file extension is a generic extension used by several different programs, but its core purpose is almost always the same: to index data for faster searching or access. Think of it like the index at the back of a textbook