Prevent Others from Sharing and Unsharing a File

You can prevent others from sharing and unsharing a file that you own. Preventing others from sharing or unsharing doesn’t affect existing shares.

1. On Files home, find the file you want.
2. Go to Sharing Settings or Share File for the file. (Or, if the file is in a library, open the Content Detail page from the Libraries tab.)
3. Select the checkbox Prevent others from sharing and unsharing.
4. Click Save.

Example

Let’s say I post a file in Chatter, and share it with a private group. I’m okay with members of the group having access to the file, but I don’t want them to share it further. I can prevent sharing and unsharing so that the existing shares remain but new ones can’t be added, except by me or an admin.