Sometimes Public Folder Exporter installation may crash due to this SQL error:
Product: QUADROtech Public Folder Exporter -- Error 26201. Error -2147467259: failed to create SQL database: FolderCleaner, error detail: unknown error.
The problem may be linked to SQL Server Browser service which is not running on the SQL Server. Make sure the service is running.
If the SQL Server Browser service is not running, start the service and run the Public Folder Exporter installation again.