This thread is a response to "WTF HAPPENED!!?! aaaaaaaaaahh!!" which is currently locked. I've Pmed a mod which was nice enough to unlock it, but I think he forgot to do it, so please if possible, merge the 2 threads.

The GW client has to finish downloading all the new data because there has been a major update for the release of nightfall. Doing this, the client has to re-download all the base files to replace the older ones. The reason why you are seeing the character selection screen as it is, is because you singed in too quickly and have not allowed enough time for the necessary files to be downloaded. The same problem happened to me.
Here’s what you do:
Open the GW client and DON’T sign in. On the top right hand corner of the login screen you can see a yellow lightning icon together with the download meter measuring the downloads in MB. You’ll have to wait for all the file downloads to finish and this may take a while. The total download is about 2GB. Once all of the downloads are finished the lightning icon will disappear and you can now login. If I am correct, all of your characters will be there unharmed and with armor as you left it.
I hope this helps and I hope it helps other who have experienced this problem .
P.s. On a side note, if you do not wait for the streaming updates to finish, they will also predispose you to a laggy game. I've confirmed this with 4 separate computers with separate internet connections. The more completed client which has downloaded all the updates will not download any further updates and will result in a smoother gameplay. However with a more basic client which is still in the process of streaming information, will continue to do so even while you are playing the game. You can confirm if your client is still streaming information by the yellow lightning icon on the top right corner of your screen.
I hope this helps again.
