Detect if restart is pending before installing in Inno Setup

Question

Is there a way to prevent installation if a reboot/restart is already pending/required?

Our setup installs SQL Server Express and it will sometimes refuse to do so if there is a pending restart in the system. Can Inno Setup detect this condition so I can tell the user to reboot before installing our software?

I know about MakePendingFileRenameOperationsChecksum but it's usually mentioned to detect whether the reboot required condition appeared DURING the setup. Can it be used BEFORE?

Answer 1

If you want to detect, if there is a pending rename that requires a restart, query PendingFileRenameOperations registry value.

See also How to find out if an MSI I just installed requested a Windows reboot?

function IsRestartPending: Boolean;
var
  S: string;
begin
  if RegQueryMultiStringValue(
       HKLM, 'SYSTEM\CurrentControlSet\Control\Session Manager',
       'PendingFileRenameOperations', S) then
  begin
    Log(Format('PendingFileRenameOperations value exists with value [%s]', [S]));
    Result := (Trim(S) <> ''); { This additional check is probably not needed }
  end
    else
  begin
    Log('PendingFileRenameOperations value does not exist');
    Result := False;
  end;
end;

function InitializeSetup(): Boolean;
begin
  if IsRestartPending then
  begin
    MsgBox('Restart your machine please', mbError, MB_OK);
    Result := False;
    Exit;
  end;

  Result := True;
end;

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If you need to test for other actions that may need restart, you will have to adapt the answer by @Jerry for Inno Setup.