Specify the registry uninstall key location/hive via [Code]

Question

Inno Setup by default looks at the PrivilegesRequired setup variable, if this is set to admin or poweruser, the installer installs the

Answer 1

Inno Setup 6 has a built-in support for selecting between "Install for all users" and "Install for me only".

Basically, you can simply set PrivilegesRequiredOverridesAllowed:

[Setup]
PrivilegesRequiredOverridesAllowed=commandline dialog

---

For Inno Setup 5: As you found yourself, the logic is hard-coded. You cannot really control that.

The closest you can get is by using the undocumented (deprecated) PrivilegesRequired=none.

With this value (and with a help of installer-autodetection in Windows):

• When you start the installer with an un-privileged account, it starts without prompting you for elevation. If you decide you need to elevate during the installation, you can restart the installer elevated.
• When you start the installer with a privileged account, it always prompts you for elevation and won't start, if you reject that. So the installer always runs elevated. Again, you would have to restart the installer, if you decide you to proceed un-elevated. See How to Start a Process Unelevated or maybe Run un-elevated command from an elevated prompt?.

It's not exactly, what you want, but I do not think you can get any closer.

---

You can of course copy (move) the registry key between the HKCU and HKLM yourself by a code:

function MoveHKCUUninstallKeyToHKLM: Boolean;
var
  UninstallKey: string;
  AppId: string;
  I: Integer;
  ValueNames: TArrayOfString;
  ValueName: string;
  ValueStr: string;
  ValueDWord: Cardinal;
begin
  if '{#emit SetupSetting("AppId")}' <> '' then
  begin
    AppId := '{#emit SetupSetting("AppId")}';
  end
    else
  begin
    AppId := '{#emit SetupSetting("AppName")}';
  end;

  Result := False;
  if AppId = '' then
  begin
    Log('Cannot identify AppId');
  end
    else
  begin
    UninstallKey :=
      'Software\Microsoft\Windows\CurrentVersion\Uninstall\' + AppId + '_is1';
    Log(Format(
      'AppId identified as "%s", using uninstall key "%s"', [AppId, UninstallKey]));
    if not RegKeyExists(HKCU, UninstallKey) then
    begin
      Log('HKCU uninstall key not found');
    end
      else
    if RegKeyExists(HKLM, UninstallKey) then
    begin
      Log('HKLM uninstall key exists already');
    end
      else
    begin
      Log('HKCU uninstall key found and HKLM key not exists yet');

      if not RegGetValueNames(HKCU, UninstallKey, ValueNames) then
      begin
        Log('Cannot list uninstall key values');
      end
        else
      begin
        I := 0;
        Result := True;
        while (I < GetArrayLength(ValueNames)) and Result do
        begin
          ValueName := ValueNames[I];
          if RegQueryStringValue(HKCU, UninstallKey, ValueName, ValueStr) then
          begin
            if not RegWriteStringValue(HKLM, UninstallKey, ValueName, ValueStr) then
            begin
              Log(Format('Error moving "%s" string value', [ValueName]));
              Result := False;
            end
              else
            begin
              Log(Format('Moved "%s" string value', [ValueName]));
            end;
          end
            else
          if RegQueryDWordValue(HKCU, UninstallKey, ValueName, ValueDWord) then
          begin
            if not RegWriteDWordValue(HKLM, UninstallKey, ValueName, ValueDWord) then
            begin
              Log(Format('Error moving "%s" dword value', [ValueName]));
              Result := False;
            end
              else
            begin
              Log(Format('Moved "%s" dword value', [ValueName]));
            end;
          end
            else
          begin
            { All uninstall values written by Inno Setup are either string or dword }
            Log(Format('Value "%s" is neither string nor dword', [ValueName]));
            Result := False;
          end;
          Inc(I);
        end;

        if Result then
        begin
          if not RegDeleteKeyIncludingSubkeys(HKCU, UninstallKey) then
          begin
            Log('Error removing HKCU uninstall key');
            Result := False;
          end
            else
          begin
            Log('Removed HKCU uninstall key');
          end;
        end;

        if not Result then
        begin
          if not RegDeleteKeyIncludingSubkeys(HKCU, UninstallKey) then
          begin
            Log('Failed to move uninstall key to HKLM, ' +
                'and also failed to rollback the changes');
          end
            else
          begin
            Log('Failed to move uninstall key to HKLM, rolled back the changes');
          end;
        end;
      end;
    end;
  end;
end;

procedure CurStepChanged(CurStep: TSetupStep);
begin
  if CurStep = ssPostInstall then
  begin
    Log('Post install');
    MoveHKCUUninstallKeyToHKLM;
  end;
end;

Answer 2

The PrivilegesRequired=none solution was not what I wanted. In some cases, it still prompts for elevation on administrator accounts and also the registry destination was still not reflective of the users selection.

Since I was already using a native helper DLL in my Inno Setup project, I coded this in C++ as I'm more comfortable there. I'm calling this method is called in CurStepChanged where CurPage=ssDoneInstall. Just call this method with the [Setup] AppId and whether or not the registry keys should be installed locally or not.

#include <shlwapi.h>
extern "C" __declspec(dllexport)
bool DetectAndMoveRegKeyW(LPCWSTR app_id, bool install_local)
{
    std::wstring s_app = app_id;
    std::wstring path =
        L"Software\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\" + s_app + L"_is1";
    LPCWSTR c_path = path.c_str();

    LRESULT res;
    HKEY source = nullptr, subKey = nullptr;

    // try to find source in HKLM
    source = HKEY_LOCAL_MACHINE;
    res = RegOpenKeyExW(source, c_path, 0, KEY_READ, &subKey);
    if (subKey != nullptr)
        RegCloseKey(subKey);

    // try to find source in HKCU
    if (res != ERROR_SUCCESS)
    {
        subKey = nullptr;
        source = HKEY_CURRENT_USER;
        res = RegOpenKeyExW(source, c_path, 0, KEY_READ, &subKey);
        if (subKey != nullptr)
            RegCloseKey(subKey);
    }

    if (res != ERROR_SUCCESS)
        return false; // cant find the registry key

    HKEY dest = install_local ? HKEY_CURRENT_USER : HKEY_LOCAL_MACHINE;
    if (source == dest)
        return true; // registry already in the right place


    // copy registry key to correct destination
    HKEY hOldKey;
    HKEY hNewKey;
    bool bResult = false;
    if (RegOpenKeyW(source, c_path, &hOldKey) == 0)
    {
        if (RegCreateKeyW(dest, c_path, &hNewKey) == 0)
        {
            bResult = (SHCopyKeyW(hOldKey, nullptr, hNewKey, 0) == 0);
            RegCloseKey(hNewKey);
        }
        RegCloseKey(hOldKey);

        if (bResult)
        {
            RegDeleteKeyW(source, c_path);
        }
    }

    return bResult;
}

I'm exporting this method as cdecl instead of stdcall, this is because VC++ ignores the C extern and mangles method names anyways when using stdcall. You'll need to import this as cdecl in inno (see inno docs for this). Also, of course this is the Unicode-only implementation, if you require an Ansi version it should be simple enough.

IMPORTANT NOTICE:
This code is incomplete, it doesn't account for 64bit registry redirection. Inno-Setup completely ignores windows registry redirection and this code doesn't search the 64 bit registry at all since Inno and itself are running in 32bit.