Hi Sean, 

Welcome to Box Community and glad to assist! 

Can you have the user to follow the troubleshooting steps below. 

• Updating your browser to the latest version


• Clearing your browser's cache


• Using Box with an alternate browser, computer, or network. 


• Temporarily disabling any internet security/firewall programs to test whether they conflict with Box (Note: you may need clearance or assistance from your organization’s IT department/helpdesk to do this)


• Temporarily disabling any plugins/extensions in your browser. 


• Restart your machine. 

Hope it works!