Lost folder

Hi there, 

Welcome to Box Community and glad to help! 

In restoring deleted folders, note that when items are deleted from a collaboration folder, both the owner and the person who deleted the item can recover the items from the Trash. 

Do you recall who owns this folder? If not, you can head over to your trash and filter the deleted items from there. 

You can filter content by items you own, or by items you’ve deleted.  To do this, directly beneath the folder label (Trash), click the Items I Own (or Items I Deleted) down arrow.  Then click the option you want.

Once you've located the deleted folder, here's how to restore 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.

To know more about your trash https://support.box.com/hc/en-us/articles/360044196093-Managing-Trash

Hope it helps!