If you are receiving an access denied warning when trying to “Replace all child object permissions with inheritable permissions from this object” then you probably don’t have permission on the files yourself.
To fix this problem:
Click on the owner tab and change the ownership of the folder to yourself and make sure you select “Replace owner on subcontainers and objects”.
Click on the permissions tab and click change permissions click add and typing in your username give yourself full control, make sure your username is selected and then click “Replace all child object permissions with inheritable permissions from this object” and let it add your permission to all the files and folders.
You can now choose another set of users and apply permissions then select that username or group and click “Replace all child object permissions with inheritable permissions from this object” It should work this time.
If there is a quota setup on the server make sure you change ownership of that folder, sub containers and objects.