Windows 7 elevated registry access

Question

I'm working on an installer for our application. The installer makes some changes to the HKEY_CURRENT_USER\Software\Company\AppName registry key, which the application then looks for the first time it runs. The application then does different things based on the registry keys it finds.

This works great, until you try to install the application as a user account (i.e. non-administrator) on windows 7 (and maybe Vista, I haven't tested that yet).

When the user tries to install the application, Windows elevates to the administrator account's credentials. This means that any changes to HKCU in the registry are made to the administrator's registry, not the launching user's registry. Thus, the keys are not visible to the application when it launches for the first time under the user's account.

We can't be the only people whose installer needs to communicate with the app it installs. Is there no way to reliably use the registry to do this?

We can't rely on the user launching the app after he installs it, so passing the information as a command-line parameter isn't a viable solution. The only way I can see to do it is to have the installer invoke a utility as the original user, which gets or sets the registry key itself; this seems to be a bit of a silly hoop to have to jump through.

Edit: The application needs to delete the keys after it's used them, so I can't just put them in HKEY_LOCAL_MACHINE.

Answer 1

There are 2 recommended approaches for what you want:

1. Use a per-user installation which doesn't require Administrator privileges. You will be able to use HKEY_CURRENT_USER, but your product is not installed for all users.

2. Use a per-machine installation which requires Administrator privileges. In this case you need to redesign your application so it reads its settings from a configuration file. HKEY_CURRENT_USER should be used only when saving user-specific settings, not for global application settings.

Basically, if your application is per-machine, it should use HKEY_LOCAL_MACHINE or a configuration file. If it's per-user, you can use HKEY_CURRENT_USER. Any other combination has limitations and will not work the way you need.