Problem:
"This file couldn't be downloaded" error on VMDK file download during OVF export from ESXi 6.7.
Common error "This file couldn't be downloaded"
Error from chrome - "Failed Network error"
Error from Internet Explorer: "The disk0.vmdk download was interrupted"
Workaround Solution:
Try to export OVF from "Mozilla Firefox".
Ovf will export without any error.