You need to open cmd.exe in Admin Mode. Right click on cmd.exe and select Run as Administrator.

If you are using Notepad, say for the Hosts file, you need to open Notepad with Run as Administrator.

How does it fix the copying files issue?

It normally allows copying to protected areas like user folders and program folders

OK. How can I disable this message permanently?

The message comes up when you need permissions , so it does not go away permanently . However you should not see the message if you have adequate permissions

I understand this. Are you saying there is no way to disable this message if the user is a member of the local admin group?

If you are admin and you are trying also to go where further elevated permissions are needed (examples above), there is no way to eliminate the message.

The security permissions on the folder may be amiss. One solution is to adjust the Security for the folder or file. Clear then reassign the users / groups.

I assume in my information above that folder permissions are correct (as is normal on a server) so please let us know if not.

The security permissions are standard -- right after the installation.

Then you need to live with the message unless you first use elevated permissions.

NEVER - NEVER disable UAC on a Server. Don't. That is the WRONG thing to do.

Question - WHY are you copying FILES to the root of the drive?  There is RARELY a good reason to do so.  You can easily make new folders and copy files to folders.  If you really MUST copy a file or two to the root, fine, deal with the error message, complete the copy - but don't do something every professional IT person I know would consider absolutely foolish - like disabling UAC!

I like the good comment option, but maybe a bad comment button is needed, for suggesting you remove UAC, I can't imagine when I'd consider doing this on a production server.

As for copying files to the Root, I can think of a couple reasons I'd consider it like avoiding local paths, being long than my User Paths, by making initial Shared C:\net but making the share "Network Shared Files" especially when moving company files from other hardware.

Basic Production Servers really shouldn't have people logged into them enough for the elevated permsions "run as Administrator" to be a big issue.

I actually found a registry fix, but as this Microsoft article says, "Under certain constrained circumstances, disabling User Account Control (UAC) on Windows Server can be an acceptable and recommended practice"