Hi Bruce, 

Welcome to Box Community and happy to assist! 

Looks like you have an issue with the file(s) you've uploaded and downloaded at the same time, am I correct? 

Could you elaborate your workflow for more context? 

We'd love to further assist! 

if I am working on a file I will save it to say "downloads."  then I go into Box and want to upload the file to a Box directory.  When I try to upload the file to Box I see the file as saved in downloads, but when I try to click on to upload, the file disappears from Finder/downloads. If I go directly to downloads I can drag it to Box, but it's more straightforward to seek to upload from Box....