I've spent the last couple hours trying to install the game on my friends computer (via TeamViewer) and we have had zero luck.
For a while, it kept saying the files were corrupt, and we had to keep redownloading them using different browsers but were finally able to get the installer to work. DirectX and POL installed fine (and I was able to update POL). But every time we try to install FFXI, it keeps bugging out and giving the same error.
We have tried everything we can possibly think of. He's running W11 (same as me and I had no issues at all). We turned off his AV, firewall, Defender, ran in compatibility mode for different versions of Windows, run as admin. There have been a lot of windows extension changes that we tried, update every driver I can find, every single possible solution and nothing has worked. SE just said to buy a new copy of the game, which we've tried downloading from numerous sources and none of them have fixed the issue.
This is the closest we have gotten, even after deleting and uninstalling everything and starting fresh, numerous times.