This has happened to me. I have been able to get it to work by retrying the download until it works, it took me three tries. If that still doesn't work, Google

This has happened to me. I have been able to get it to work by retrying the download until it works, it took me three tries. If that still doesn't work, Google Takeout supports splitting the download into smaller 1 gigabyte chunks which should hopefully be downloadable fast enough. Still annoying though.