I'm moving a new client from v13 to v17, and normally closing the database and downloading to zip works (and maintains image links when uploaded to the new server).
In this case, a file with an images folder that totals 40gigs is purportedly downloading, and I'm staring at this, with no temp folder appearing in the Download folder.
Reading this article https://community.filemaker.com/message/489773?commentID=489773#comment-489773
I am going to assume as the total load exceeds 2gigs (the file, or the images?), I'm not going to have luck, and go with a Plan B; moving by hand as described here FileMakerPKB
If you folks think of any Gotchas let me know.