Description: This solution describes how to resolve the error: "An error occurred opening the report: 'Failed to load expression host assembly. Details: Object reference not set to an instance of an object'."
Environment: Not hosted
Version: All
Answer:
This error occurs when trying to run the appeal analysis report from SegmentOmatic.
Microsoft Report Viewer 2010 must be installed on the workstations accessing the analysis report.
You can install it from the Microsoft website.