On Tue, Nov 26, 2019 at 09:51:51PM +0000, Baron wrote:

> The output from "file" is,
>  
> "RAR archive data, v0, flags: Locked, Authenticated,"
> 
> Which doesn't help me a lot I'm afraid.

My guess is that this means that your RAR file is password protected and 
your unrar utility doesn't know how to deal with it, but that's a guess 
because I'm busy and don't have time to research it for you. But I 
seem to vaguely remember having this same problem in the past, which I 
ended up solving by running the unrar utility from the command line 
rather than through KDE's Extract menu.

But that was years ago and I might be confabulating the whole episode.

You could start some more research here:

https://duckduckgo.com/?q=rar+locked+authenticated



-- 
Steven