We recently installed Vista RC1 and tested an application that we distribute and immediately ran into problems. Naturally, the UAC (User Access Control) is the problem that we did not anticipate or even know about until we installed Vista.

For those that are familiar with the problems that UAC can cause, it appears that you should be developing your apps to run for "standard users" instead of "administrators". In the XP world, seems like everyone was an administrator and Vista is going to change this.

In short, no more writing to the "Program Files" or "Windows" folder; and no more registry changes UNLESS you want to logon as an administrator to do this.

We've decided to try and modify our apps so that they will run in XP or Vista without any special code or even knowing if they are in Vista. Here is what we determined.

I know Rick Strahl (correct me if I'm wrong here Rick) suggested using
SYS(2023) to determine the folder to your application system files. Currently, these are being stored in the application folder in Program Files... which is a big no-no under Vista.

In our testing, SYS(2023) did not give us consistent results. In XP, on one occasion it was returning the C:\ folder. Conceivably, this was due to a setting in the config.fpw or an application config.??? file. We decided that this was too difficult to control because what is returned by SYS(2023) could be changed by a setting in the config.??? file.

After reviewing the environmental variables that exist in both Windows XP and Vista, it looks like the ones that will give us what we are looking for is either the APPDATA or USERPROFILE environmental variable.

The following shows an example of what we would do if using the APPDATA variable to determine where our applications system files should be created.

In Win XP, Appdata returns ...

C:\Document and Settings\UserName\ApplicationData

In Vista, it returns

C:\Users\UserName\AppData\Roaming

(Note: We'd probably strip off the "Roaming" so as not to run into problems with roaming profiles, and append on "Local" to save in the Local application data folder.)

To this we would create a folder for our application and store our application files that the user creates when running the application in that folder.


Here is an example of how this would work:

User name is: John
Application Prefix is: JJF

If running in XP we would save our application system files in:

C:\Document and Settings\John\ApplicationData\JJF


If running Vista, we would save our application system files in:

C:\Users\John\AppData\Local\JJF


If anyone else has given any serious thought to this, I'd sure love to hear your comments.