If this code in constructor of WimFileSystem throws

ShortResourceHeader metaDataFileInfo = _file.LocateImage(index);
if (metaDataFileInfo == null)
{
throw new ArgumentException("No such image: " + index, nameof(index));
}

_metaDataStream is never set

Later the GC will call the deconstructor in DiscFileSystem Dispose(false) that will throw when _metaDataStream is not set

This is a major problem for us when trying to work with a corrupt wim-image.