Am I the only one?

[bkjohns]

If you can get your hands on a Windows 10 machine, install XDP on that and try it. Might be the version of Windows causing the problem, although this sounds exactly like the issues everyone experienced when 12.6 first released and was fixed in following updates (12.6.2 I think).

[Donald33]

(As Egg and bk posted about your computer) By chance have you opened the task manager and checked your resources while uploading? You could be running out of memory and see what is happening with the network connection. Does your host have a timeout or limit on an upload? Are you using the 64 bit version? Could your hard drive be close to max and not enough swap space?

Just some thoughts.
Regards