Vista UAC - Trouble Mapping Network Drives

Question

We have an application that programmatically maps network drives. On Vista with UAC on, we get some strange issues.

Our application maps the drive non-elevated, so if the user browses explorer and double clicks to run an exe, it prompts for UAC. So when they approve it, it prompts for a username/password for the share... Strange since the credentials are saved.

It turns out, an elevated process cannot access a mapped drive that was mapped from a non-elevated process.

To see this issue in action, do the following steps:

• Run cmd.exe with no UAC
• Run "net use w: \yourHostname\yourShare /user:yourUser yourPassword /persistent:yes"
• Run cmd.exe as Administrator
• Type "w:", and see the error message

At this point you can run plain "net use" and see the connection on the elevated cmd is Unavailable but the other non-elevated cmd sees it as OK.

Does anyone know a workaround to fix this issue? or maybe a way to map a network drive to "All Users"?

Answer 1

Check out this link: Regedit Link

They describe a registry key that allows elevated users to access mapped drives and vice versa. This solves all my issues and was exactly what I was looking for.

EDIT:

The original link is dead, but here's the text as copied from the Jan 24, 2009 snapshot at www.archive.org:

---

If you are finding that you don't have access to mapped drives from your admin token try the following. When running as a protected admin you have two tokens and this key will maintain the connection for both tokes (that is my understanding anyway). It can also help to clear up issues with Login scripts.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System EnableLinkedConnections =(dword)1

Also of use is the "'Group Policy Scripts can fail due to User Account Control" section of this doc.

http://technet2.microsoft.com/WindowsVista/en/library/5ae8da2a-878e-48db-a3c1-4be6ac7cf7631033.mspx?mfr=true

I will be posting more information on this soon.

Answer 2

This is by design.

Even though the user account is the same, with the elevated version having a token with membership in the administrator group and addition privileges, the tokens are created independently and thus have different LUID's and appear to the kernel to be from different user logons. Since they are from different logons, mapped drives are not shared between them.

http://blogs.msdn.com/cjacks/archive/2007/02/19/mapped-network-drives-with-uac-on-windows-vista.aspx discusses this in additional detail.