Do you have any video filters or codec packs installed, etc?
Is there a name on the window that pops up, like 'Active movie', or something? (that caused a problem for a couple people with cutscene videos in Divinity 2, see
here, though D:OS is a different game engine using different video encoding)
Please email supportdos@larian.com, with a description of the problem (possibly a screenshot) and the report.zip file generated by the
D:OS support tool (for the PC version). The report will contain system and game information, any crash dumps, and your saved games. If file size is an issue, any saves not related to the problem can be deleted (you'd probably only need to keep your latest save).