Continue moving files when process stopped
If the source has the same number of solid files as the destination has translucent, it is safe to manually resume the move. Drag and drop to move from source to destination, and select "replace" when prompted. Translucent files are just empty placeholder files.

My personal practice always involves copying, then deleting once done. To insist on a copy, hold down Option. It's a bit more tedious but it's saved me much frustration over this sort of matter.