Error when attempting to run Model Checker

[jessicacardinal]

Could not load type 'ADSK.BIT.ModelChecker.API.Services.Implementation.PreBuiltOptionsService' from assembly 'BIT.ModelChecker.API, Version=8.0.7921.0, Culture=neutral, PublicKeyToken=null'. Developer Info: at Cohort.RevitTaskPlugins.ModelChecker.Execute(Task t) at CohortRevitTaskServer.Controller.runOneTask(String artifactPath, Document& doc, OpenModelOption openModelOptions, String loadErrors, KeyValuePair`2 oneTaskToProcessor, TaskWrapper parentTask, SecurityManifest security)

[jeremy_tammik]

I don't think there is much we can say about that here in the Revit API discussion forum, I'm afraid. 

Please note that this discussion forum is dedicated to programming Revit using the Revit API. Afaict from your description, you are not doing anything programmatically yourself using the Revit API, just using the standard Revit user interface and the model checker add-in. In that case, you will probably get more optimal answers to a question like yours relating to product setup, optimisation, usage, best practices and other end-user support issues in one of the non-API Revit product support discussion forums instead:

https://forums.autodesk.com/t5/revit-api-forum/this-forum-is-for-revit-api-programming-questions-not...

I hope this clarifies. Thank you for your cooperation and understanding.

Best regards,

Jeremy