Now when I start (v1.0.3.0), I get a window with this error. When I close this window, the main window closes also. There is no possibility to go the settings.
What does it mean? How to disable this mode?
That was your mistake, pruning isn't implemented yet. To reverse open veil.config and remove any line found there then edit bPrune key in registry by setting it to "false" (\HKEY_CURRENT_USER\Software\Veil\Veil-Qt).
Maybe it looks like nooby, but I did not find veil.config. In the registry, I changed the value to false. Now I can open the wallet. But when loading blocks, the wallet sometimes closes.
Backup made. I will try to reinstall the wallet.
you can create the veil.conf file in the appdata folder.
Still though, there is no need to create it, if you just want to open the wallet to stake and you get nodes to connect to.