[If you've just downloaded the game for the first time, you can safely ignore this message]
For debugging reasons (details here
), the lobby client launcher/wrapper (but not the client itself, once you log in) will re-download the latest Zero-K stable as an .sdz archive instead of the 'rapid' incremental format currently in use. This will occur even if you already have the newest stable downloaded via rapid, but will only happen once per stable ZK release.
Due to the large file size involved (275 MB), this will lead to some wait time the next time you try to launch the game. To do the downloading ahead of time:
Go to this page
Download zk-v126.96.36.199.sdz to <gamedata folder>/games (this will usually be where you installed/downloaded the lobby client executable Chobby.exe to)