If you’ve come across a file with the .idx extension and can’t open it, don’t worry—you’re not alone. The .idx extension is used by for different purposes. It is rarely a standalone file; it usually works alongside another file (like a .sub , .bak , or .dat ).
A label design file for LightScribe disc labeling technology (now discontinued). The .idx stores layout information. how to open .idx
Deleting a subtitle .idx is fine (you lose subtitles). Deleting a database or email .idx could cause crashes or data loss. If you’ve come across a file with the
Do not try to open the .idx file by itself. Instead, configure your media player to load it along with the movie: Download and install VideoLAN VLC Media Player . A label design file for LightScribe disc labeling
Many legacy applications use .idx files to cache search directories, document systems, or index mailboxes. These are often plain text formatting under the hood. How to Read the Contents What are .idx files? - Microsoft Q&A
That will help pinpoint the correct tool.