Hi,
I just purchased Spriter Pro version through Steam. I found, that:
- I have to be logged into Steam otherwise I can not run app - it starts and closes immediately (no error messages),
- even if logged into Steam account, it is not possible to open .scml/.scon file with double clicking on it in explorer - Spriter starts, loads file (I can see it) and then ends immediately (no error messages). It is necessary to first start Spriter and then open file in it with file->open.
I also tried free version from your site and it does not suffer from this, so it seems all this is related to Steam version.
Tom