Why can .NET app not overwrite file when user is Administrator?

Question

My WPF app downloads and caches files to the C:\\ProgramData\\CompanyName\\ProductName\\Data\\ directory.

If another user was logged in when they downloaded (created) the file, I cannot overwrite the file to update it, even though I am an Administrator.

Why do I not have write access when I am also an Admin user?
The screenshot shows the file permissions of a file I cannot overwrite.

I understand that I have to elevate the process to do an 'admin' task ( as explained here ), but seeing as the other user was an Administrator (and so am I), and the 'Owner' of the file is 'Administrator' - why don't I have write permission on a file where the Owner is in the same group? Why don't we share the same privileges?

Answer 1

After downloading and saving the file you may set full access for all users (or any other appropriate group) by code like this:

var fileSecurity = File.GetAccessControl(path);

fileSecurity.AddAccessRule(
    new FileSystemAccessRule(
        new SecurityIdentifier(WellKnownSidType.BuiltinUsersSid, null),
        FileSystemRights.FullControl,
        AccessControlType.Allow));

File.SetAccessControl(path, fileSecurity);