Remember Square Enix ID tickbox doesn't work

When I start the game using ffxivboot.exe (and I don't have any other way to start, just being clear) I get a nice launcher window with a tick box labeled "Remember Square Enix ID". If I leave it empty, the launcher will require me to enter my user name when I start the launcher again, which is what you'd expect. However, if I tick the box, I still have to enter my user name the next time I fire up the launcher.

I don't think this has ever worked for me, and certainly not since 2.1. It looks like this issue has been reported at least once but it's in the Not A Bug forum, so I suspect it isn't being addressed.

Using the Run as Administrator on ffxivboot.exe doesn't help this problem. I'm running Win 7, if that makes any difference.