Windows 11 won’t open an Open Document File unless a suitable word processor is installed. A recent version of MS-Word should open odt with no bother. An ancient version might not.
Nigel’s mention of Media Player and Firefox suggest he’s trying to open the odt with File Explorer, or perhaps from inside an email client, and the association is missing. Some of the ways file associations can be added on Windows are explained on this website. Much more available – ask Mr Google.
May be easier to start MS-Word and open the file directly. Or LibreOffice.
Firefox may be worth pursuing – on my machine it displays odt files by starting Libre Writer. But I already have LibreOffice installed, not Word. Microsoft have a bad habit of elbowing other software out of the way, so if Word and LibreOffice are installed, Microsoft may have overwritten the odt association set up by LibreOffice’s installer.
Nigel’s comparison between Victorian valve gear and the profusion of computer file types has legs, except for the assumption that customers want simplicity! They do, except copyright, patents, cheapness, functionality, efficiency, security, reliability, reputation and gee-whizz advertising tend to take priority. Oh, and what can be done with computers is far more complex than valve gear, and, so far, there is no end to computerisation in sight. Each new development is likely to add another file type, perhaps several, no doubt confusing everybody for the next 10 years!
As with Artificial Intelligence being the best hope of rendering computer error messages comprehensible, so too is AI best hope for sorting out file association and similar glitches. Rather than forcing the user to look techie stuff up and fiddle with configuration settings, an AI capability inside the computer could automate diagnosis and fix. It’s coming: the latest generation of microprocessor chips incorporate machine-learning hardware.
Dave