Monitoring desktop client hardware, operating system and application faults can be of great value in terms of reducing total cost of ownership (TCO) through identification of widespread faults in the monitored environment. In Operations Manager Agentless Exception Monitoring (AEM) can help you with that. AEM enables you to monitor operating systems and applications for error. Client monitoring configures clients to send error reports to an Operations Manager Management Server. With the reporting function client monitoring mode can then generate reports based on these errors. AEM clients don’t need a agent and all client settings are controlled by a group policy.
This week I tested to run AEM between two un-trusted Active Directory forests and it seems to work fine. The biggest challenge is to get name resolution to work, to find a common share where to write error logs and also the design of Operations Manager. Each computer that reports a application error with AEM will be seen as a Windows Computer, with unknown state. Therefor you might want to use a dedicated management group for AEM and client monitoring in general. In the picture below you see a AEM view from the OM12 console, including errors from two different forests.
More info around AEM here.