Let us assume you have manually classified a device into Windows2008 category and then go on to apply the Win2008 template to the device, to associate the monitors. The template will not be applied properly if:
1. You are running OpManager on Linux and the template has WMI-based monitors.
2. You have installed on Windows, but have not configured the WMI authentication credentials for the monitored device (in this case, the win 2008 device)
3. The device has SNMP and you have not provided the SNMP credentials for the device.
Configure the credentials for the device and proceed with applying the template.