Hello Kermic,
Thank you very much for your post. I will try to clarify a few things, hopefully answering your questions.
This is about a VM running on the free ESXi Hypervisor, so there is no vMotion function available. Also the virtual disk of 2TB is independent, so it has nothing to do with the snapshots. And finally I tried to migrate the vmdk with "veeam Backup & Replication 6.1" (the free one) and not through the vSphere Client. vSphere client was giving an error too, but I didn't keep a screenshot. I will give a try now with vSphere client and will post anything newer.
Thanks a lot!
Kind regards,
Angelos Pitsos