Assuming you’ve already downloaded and installed the FFXI client from SquareEnix, you’re ready to connect and begin updating your files.
This is a LONG step. Depending on your internet speed, this could take up to 6 hours as the FFXI servers still check and update a single file at a time.
12345678a the username, password, and account ID for your new account. This just allows you far enough in to access the file check.
\Program Files (x86)\PlayOnline\SquareEnix\PlayOnlineViewer(or to where you installed FFXI) and copy the
\datafolder. Navigate to the
\Program Files (x86)\PlayOnline\SquareEnix\FINAL FANTASY XIfolder and paste that folder in that folder. You should now have a
\datafolder in your
\FINAL FANTASY XIfolder.
If you’re coming from the Nasomi player community or have ever used their installer, there’s a process to patch your installation to work with “retail” Final Fantasy XI. You can see the full instructions here: https://nasomi.com/wiki/index.php?title=Config:Installing#Retail.2FNasomi_swap.