In 4Dv18 the logs generated from MSC features have been relocated. In older versions the logs would be placed in a "Logs" folder next to the database structure. In v18, the logs are now placed in the following locations based on the OS:

Win - {Disk}:\Users\\AppData\Roaming\4D\{Database Name}\Logs\

Mac - {Disk}:Users::Library:Application Support:4D:{Database Name}:Logs: