This is not my problem but its not something I've come across before so I'm hoping somebody here has an explanation/solution because I'm stumped.
Its from a Reddit user so I hope it is OK to post the link:-
https://old.reddit.com/r/originalxbox/comments/x2rn3u/help_dashboard_is_missing_how_do_i_fix_it/
The title says it all - the guy has FTP access now and, I think, that's due to a SID/AID disc and FTP access. He posted a link to a screenshot of his Xbox drive content and it it looks to me as if there is no E:\drive. Using SID rescue options I have zero experience so if somebody here has that knowledge and/or a solution it would be useful general Xbox information worth posting here for the future reference of all OGXbox users.