Hello,

To reactivate a deactivated collaborator in Box, follow these steps:

Log in to Box: Go to your Box account and log in.
Navigate to the Folder: Go to the folder where the collaborator was originally added.
Manage Collaborators: Click on the “Share” button or the “Collaborators” tab.
Add Collaborator: Enter the email address of the deactivated collaborator in the “Invite People” field.
Set Permissions: Choose the appropriate permission level for the collaborator.
Send Invite: Click “Send” to re-invite the collaborator.

This should restore their access to the folder.

Best Regards,
Florence Gayhart
Official Site

Hi Kimberly,

Welcome to Box Community and glad to assist! 

You can inform the deactivated user(s) to contact Box Support to look into his/her deactivated status or just setup a new account.

Thanks for posting!