[Disclaimer: This tip addresses a specific issue. If you’re not faced with this issue, don’t follow these instructions.]

In many offices, some programs are installed from a mapped network drive or require access to a mapped drive as part of installing the program. The setup program starts, the installation goes part of the way, and then puts up a dialog box for one reason or another asking where the mapped drive is.

And I’ll be damned, the mapped drive has disappeared. No N: drive or K: drive or whatever was there a moment ago.

It’s not gone. You can click on Start / Computer and see the drive just fine. But the install program stubbornly refuses to see it no matter how many times you click Browse.

It seems to happen frequently with line-of-business applications. I run into it all the time in law offices with Time Matters, Orion, A1 Law, and other case management programs. Time Matters, for example, stops the installation when it can’t find the database. The same thing happens with some of the management tools for working with networked database applications.

It took a while to figure out.

When you install a program in Vista or Windows 7, you always get a User Account Control window asking you if you want to proceed. That’s the window where the screen fades to grey until you click Allow or Cancel. [It seems to annoy people who don’t realize that it would be a good thing to be asked before the Russian mafia is allowed to install a program on your computer. Anybody who thinks they’re not under attack isn’t paying attention.]

When UAC permits the installation to go forward, it’s as if a different user has slid into your chair with administrator permissions. The problem is that your Superman administrator token isn’t told about the mapped drive. The technical details are spelled out here as clearly as they can be.

There are two workarounds.

The first is to disable UAC for the installation, then enable it after the program is installed. There’s a checkbox in the User Accounts window to disable UAC; it requires a restart to disable it, another one to re-enable it. That’s often enough to solve the problem but it’s not permanent. If you need to run the program later with administrator privileges for some reason, or if management tools require administrator privileges to run, you’ll be facing the issue again and again. I know. I’ve been there.

Microsoft has documented a permanent workaround, although they don’t like it very much. (“This workaround may make your system unsafe. Microsoft does not support this workaround. Use this workaround at your own risk.”) There is a registry setting that allows a mapped drive to be shared by your user account and by your Superman administrator account.

    To work around this problem, configure the EnableLinkedConnections registry value. This value enables Windows Vista to share network connections between the filtered access token and the full administrator access token for a member of the Administrators group. After you configure this registry value, LSA checks whether there is another access token that is associated with the current user session if a network resource is mapped to an access token. If LSA determines that there is a linked access token, it adds the network share to the linked location.

    To configure the EnableLinkedConnections registry value, follow these steps:

    1. Click Start, type regedit in the Start Search box, and then press ENTER.

    2. Locate and then right-click the following registry subkey:


    3. Point to New, and then click DWORD Value.

    4. Type EnableLinkedConnections, and then press ENTER.

    5. Right-click EnableLinkedConnections, and then click Modify.

    6. In the Value data box, type 1, and then click OK.

    7. Exit Registry Editor, and then restart the computer.

    I lost a lot of hours before I finally tumbled to this trick. I don’t feel like that registry entry causes a serious security issue in small offices and it permanently fixes this issue for programs that are sensitive to it.

    There are lots of tips online that involve editing the registry. Here’s the obligatory warning, in case you haven’t seen it lately.

    dangerCareless registry editing can cause irreversible damage to your computer. Do you see the word “irreversible”? Do you have it clearly in mind? You can kill your computer in seconds by mucking around in the registry. Don’t go there unless you are 100% sure of what you’re doing.

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