Hi Anita, 

Welcome to Box Community and glad to help!

You can start by finding out whose folder it is. And the owner should check his/her trash/bin icon to locate and recover the missing files. 

If the missing file is in trash, the owner can restore specific items in Trash:

The steps below apply whether you’re selecting from search results or from all Trash items.

1. Hover to highlight the row of the item you want. The More Options ellipsis (…) displays.


2. Click the ellipsis (...).  Then: 

• To return the item to its original location in Box, click Restore.

3. At the prompt, click Okay.

Hope it works!