Hi Kugimiya, 

Welcome to Box Community and glad to assist! 

There are only two reasons your missing contents are not in trash: 

1. The contents have been removed from trash. Box stores files and folders you place in Trash for a certain period of time, that default period is 30 days.


2. You're removed as collaborator. It happens when your access to a shared folder has disappeared. 

As for the latter, you may contact the file/folder owner to help with your content recovery or collaboration permission. 

Thanks for posting! 

thank you for your reply.
On April 23rd, I accessed Box for the first time in several years.
At that time, I confirmed that multiple files exist.
When I accessed it again on April 28th, all the files were gone.
There was nothing in the trash can either. I haven't shared my files with anyone. Is there any way to restore the files?