ffxiv unable to complete version check [30410] [30607][20457][404]

Yesterday I patched the game to 4.01 and started the game, all worked fine, but then my PC froze (the problem is probably unrelated to FFXIV)
After I started up I got the error message "ffxiv unable to complete version check [30410] [30607][20457][404]" after I tried to log in. I tried the solutions I found like reseting connection, change some numbers in the bootfile but none helped so far.

I assume that during the crash some version check file was corrupted, but I have no idea how to fix it.

What I tried that did not work:
reinstalling the game
reseting all connections
making the whole folder under my documents not "read only"
run as admin and with compabillity to old windows

edit:

Ok, so I am one step furhter. The issue is the file
C:\Program Files (x86)\SquareEnix\FINAL FANTASY XIV - A Realm Reborn\game\ffxivgame.ver
if I use my old file (I made a backup before reinstalling to avoid the downloads) it still gives me the error. If I use the new file, I have to redownload 28GB but it works. Now if I could only know how to fix the old file

Yet another edit:
so ok
so yes
I managed to "only" have to download 8.7GB
Don't ask me what these are for I do not know. I backuped the whole folder but whatever. But I ll just take that.
How I got around the biggest part of the download: There is a file in the same folder with same name but its a .bck (backup) which still had the correct version in it. I guess they put it in for cases like this, but don't automatically use it. So both great job and poor job at once there :) The solution is obvios: If you get the error, make a backup of the original file just in case, then replace it with the .bck file.
I am not sure if this violates the whole agreement not to edit game files, as I did use a premade backup file to do so and not make anything of my own. I hope this did not break any rules. If I did, I am someone else, please ban that guy :)