When destination drive is full, ask user for the next destination, then continue there.
When next destination is selected and this is a single file with extra larger space, teracopy must ask if we like to split the file realtime so that later the user can merge it using the both the external harddisk. I hope you have time for some comments in my blog. https://ideas.codesector.com/communities/1/topics/262-teracopy-anywhere-but-everywhere
Customer support service by UserEcho