I upgraded to Win10 a few days ago and the game has been running fine through last night (August 3rd). This morning ( August 4th) when I try to login, I get this while trying to start the game from the launcher:
Unable to launch FINAL FANTASY XIV Updater
[11035] [30425] [30415] [5] [19900] [5]
(filepath to ffxivupdater.exe here)
This happens after using the standard FFXIV launcher with version number 2015.06.12.0000.0001 at the top as usual and the same with (1543683) at the lower right above the Facebook/Twitter/YouTube buttons. I enter my ID and password, it goes to "Checking FINAL FANTASY XIV" longer than usual, then <blip!> with the above-stated error message from the launcher. Not really wanting to uninstall/reinstall seeing as how it was working fine 12 hours ago with no downtime maintenance since the last time I logged in.