xzip_create doesn't create anything, sandbox is disabled.
When I call the function, game freezes for a second so I guess it's doing something, xzip_create returns the correct path, but there just is no file created.
xzip_exists also returns false when I enter the path I got from xzip_create.
To keep it simple for the test, I just tried to zip projects .yyp file.
Viewing post in Xzip - Archive Format for Games comments
Hi, thanks for using Xzip!
Please keep in mind that even with the filesystem sandbox disabled, GameMaker projects are still subject to Windows filesystem permissions. Most likely, the application does not have permission to access your project directory. If needed, you can give GameMaker access to protected locations with the "get_open_filename" or "get_save_filename" functions, then pass the returned file path to Xzip functions.
Xzip does attempt to validate access permissions on its own, but GameMaker can silently redirect filepaths to the sandbox in some cases, so you may not be getting an error if, say, the file is being created under %AppData% instead.