However, things changed with Windows 11/10/8. In Windows 11/10/8, Index.dat files are not used by Internet Explorer 10. The indexing functions are being implemented within a Microsoft database system.

Q. I sometimes receive e-mail messages with a “winmail.dat” file attached that I cannot open. Why does this happen, and what can I do to fix it? A. The winmail.dat file usually appears because various ...

We’ve all seen mysterious .dat file attachments in our inboxes from time to time. In most cases the .dat attachment originates in Microsoft Outlook, which produces outgoing messages using a slightly ...

Letter Opener converts winmail.dat attachments on the fly, so you can actually see and use the attachments the sender intended you to have. [Editor’s note: The following review is part of Macworld’s ...