By default, the IQ service logs (IQ Application, IQFolder, IQocr, ServiceHost, etc) and Add-on logs are located here on the IQ Server: C:\WINDOWS\Temp\Informa Software\Logfiles.
The IQ client logs are stored in the following location on the client machines: %temp%\Informa Software\LogFiles.
Note: The AppData folder is a protected operating system folder and is hidden by default.