Error Message 1500 appears when Windows thinks another installer is already running. This usually happens when more than one Windows Installer process is open in the background. To fix it, open Task Manager, end any Windows Installer tasks, then restart your computer. After restarting, you can install Boulevard again.
- Ctrl + Alt + Delete to launch the Windows Task Manager.
- Select any Windows installers that are running, then click End Task.
- Restart the computer, then proceed with installing Boulevard again.
