Windows Server 2008 File Sharing for users in Administrators group

Ok here is probably dumbest question but I really dont understand how sharing works.

I shared a folder with name "Data" and I gave permission to "Administrators" group to everything in Network Sharing Permissions.

On the folder "Data", apart from the usual permissions, I gave "Administrators" group full control to "Data" folder.

Now I added a user in Local Users with name "DataUser" and I made this user member of "Administrators".

Simply:

1. LAN Server (No Active Directory, No Domain, Standalone Server)
2. We access via IP address.
3. "DataUser" is User and is member of "Administrators"
4. "\Server\Data" is shared folder with "Administrators" group being full rights
5. "Data" folder has full control for "Administrators" group
6. I also did "Replace all permissions on child objects" for "Data" folder

Now the problem is, I am on other machine, I can add a new file inside "\Server\Data" folder but i can not delete or overwrite the files which are there right from beginning.

Entire Data folder and its all files have full control of "Administrators" group then why user "DataUser" which is in "Administrators" group cant delete existing files? The newly added files can be deleted but not the old ones. If I right click, I can see old file has full control for "Administrators" group.

This behavior is a byproduct of the UAC being enabled. The UAC basically filters away your Adminisrator access to protect you from yourself.

You can either choose to disable it, or you can choose to add yourself to another group, and use another group when you are setting up filesystem/share access.