Skip pages when updating existing installation

Question

How do I have InnoSetup skip the license agreement page as well as the page asking if the user wants to create a desktop shortcut when the there is already an existing installation? I do want these to show on the initial installation.

When the app has already been installed, I would like minimal button presses needed in order to install the update. No need to have the user accept the license agreement again, or specify if desktop shortcut needs to be added. I push out regular updates and want it to be as un-obtrusive as possible.

See [Inno Setup: Disable components page on upgrade](https://stackoverflow.com/q/18529370/850848). — Martin Prikryl, Feb 12 '20 at 06:19
@MartinPrikryl That got me on the right track, thanks. I'll post my working solution below. — lucky.expert, Feb 12 '20 at 16:42

score 2 · Accepted Answer · answered Feb 12 '20 at 16:43

Here is what I got working - this skips the license page as well as the tasks page:

[Code]
function IsUpgrade: Boolean;
var
    Value: string;
    UninstallKey: string;
begin
    UninstallKey := 'Software\Microsoft\Windows\CurrentVersion\Uninstall\' +
        ExpandConstant('{#SetupSetting("AppId")}') + '_is1';
    Result := (RegQueryStringValue(HKLM, UninstallKey, 'UninstallString', Value) or
        RegQueryStringValue(HKCU, UninstallKey, 'UninstallString', Value)) and (Value <> '');
end;

function ShouldSkipPage(PageID: Integer): Boolean;
begin
if IsUpgrade then
  begin
  if PageID = wpLicense then
    Result := true
  end;
  begin
  if PageID = wpSelectTasks then
    Result := true
  end;
end;

Skip pages when updating existing installation

1 Answers1