Hi Barbara, 

Welcome to Box Community and glad to help!

Kindly disable your shared links individually by setting an expiration date and here's the steps: 

To set an expiration date on a shared link

1. In the Share window, click Link Settings. The Shared Link Settings window opens.


2. Under Link Expiration, click Disable Shared Link on. The Choose Date box displays.


3. Click the calendar icon and then locate and click the date you want.


4. Click Save.

When you place an expiration date on a shared link, the file or folder to which the link goes displays throughout the Box interface with a small red clock icon. 

Or you can disable it by clicking the Share window and click the slider that'll remove your shared link. 

Hope it helps!