Please refer to the hyperlink below.
Controlling site creation permissions | Alfresco Documentation
This does not remove the menu option, but users not in the nominated group cannot create a site.
In the example provided the Create site permission is granted to GROUP_SITE_CREATORS
org.alfresco.service.cmr.site.SiteService.createSite=ACL_METHOD.GROUP_SITE_CREATORS
You will need to create a group called "SITE_CREATORS" and assign people to it.
You can also substitute this with the following line so that only the role "Administrator" gets access.
org.alfresco.service.cmr.site.SiteService.createSite=ACL_METHOD.ROLE_ADMINISTRATOR
It is good practice to create a folder and keep all your changes in there, so when you upgrade, you can re-apply them.
My file is attached and is stored on D:\alfresco-comm_v5_2\tomcat\shared\classes\alfresco\extension
