OK thank you . Next time I'll select 'Upload new version'.
I'll let you know if it works.
But if there is only 1 main file anyway and has the same name as the predecessor, why does the message 'Mod can be updated (but you will have to pick the file yourself) when there are no other files to choose from? I mean, even if Vortex doesn't recognize it correctly, the current file would be the only option anyway, since there are no other files than this one.