Hi, I'd like to thank you for posting this, I had thought Altana Viewer had been dead and forgotten. I'd like to help with sorting some ancient issues Altana Viewer has been plagued with, so I'll go ahead and list the ones I can remember here and hope they can finally get fixed.
Music: Treasures of Aht Urhgan, Wings of the Goddess, Abyssea and Seekers of Adoulin all do not play any of their tracks when selected. This has been an issue for as long as I can remember and haven't heard of anybody really explaining why this is the case. Also, Rhapsodies of Vanadiel should have a few new music tracks to add in for its own mini folder.
Headgear: I've noticed that a few select headgear displays the gear but removes the face. Gavialis Helm, Rabbit Cap, Eschite Helm, Agent Hood, Terminal Helm, Odyssean Helm, Herculean Helm, Rarab Cap, White Rarab Cap. It's not really even a big problem and might not even be correctable but I thought I'd just toss it in there.
HQ .DATs: When doing some .DAT swapping, sometimes depending on the .DAT file you swap in, the textures for the new higher quality .DAT are an absolute mess inside Altana Viewer, but look the way the creator intended while viewed in-game. This can lead to a lot of problems and might be one of the main reasons that has contributed to FFXI's modding scene fading out of existence. Most modders I've seen no longer even play the game, and they never actually had a way to see their own mods being used within FFXI to check for blemishes or broken stuff, so they entirely relied on others downloading them and testing them out before knowing if they worked or if something was bugged out. Being able to fix the problems with HQ mods being stretched and distorted all to hell in Altana Viewer would definitely be nice not only for the person modding their game, but for the mod creators themselves. I'll attempt to attach an example of this below to display what I'm talking about for reference. Not sure if it'll work though, as I'm not used to forum posting.
If the image worked, then the textures on the left are what's seen within Altana Viewer. The textures on the right are what's intended to be seen in-game.
One final thing I'd like to add is something I've been desperately wanting for years to be possible. I'd like it if there was a tab that let you pick from a list of effects that display on the player model such as Afterglow colors, Weapon glows like Naegling's or Karambits or the small sparkles you see on some of the old VWNM body pieces like Heka's Kalasiris. Being able to pick from a list of those special effects would be a really nice new addition to this program if it's at all even possible.
That's all I can remember at the moment, but if there's anything else, I'll be sure to bring it up. Thanks again for reviving this program, it really has been extremely useful since its creation.