Unable to update patch files.

[xEthan]

You did try without setting Compatibility mode?
And run as administrator?
Could you also check the folder where it's installed and check that it's not marked as read only?

1. Right click your FINAL FANTASY XIV - A Realm Reborn folder
2. Click properties and untick Read only.
3. Click apply and then OK.

I wasn't going to answer because there was a huge gap in time between the question and the reply but gooooooo you! I would also add that I use Windows 8 and the client works just fine if that was a concern of the OP.