Why does VASSAL hang (with the window going white) when I open a scenario?
Images (such as nationality flags and VASL counters) cannot be stored in the
.vsav file itself, and so must be stored elsewhere, and VASSAL loads them from there.
There are two places these images can be loaded from (configured in the Settings dialog):
from this program: in this case, the
vasl-templatesprogram must be running before you open the scenario, otherwise VASSAL will be trying (unsuccessfully) to load images from it, and it waits a long time for each image before giving up.
If you are playing with someone over the internet, they must also have
vasl-templatesrunning, otherwise they will have the same problem.
from the internet: in this case, VASSAL will download images from the internet, so you must have a working internet connection. Unfortunately, VASSAL is a little slow downloading images, but be patient, and the scenario will eventually appear.
For fastest results, disable images completely (by unchecking all the options in the Images in scenarios box in the Settings dialog) - VASSAL will then load scenarios instantly (but they won't look as good).
Is there a Mac version?
If you are using a Mac, you should run the program using Docker (recommended), or from source.
While it's possible to compile the program and package everything up in the same way as the Windows version, I don't have a Mac, and so can't provide one. It's a very simple process, so if you're running from source and would like to put together a release, let me know and I'll make it available to everyone.