You are attempting to deploy your Reporting Services report from Business Intelligence Development Studio or SQL Server Data Tools. You hit Deploy, and ….. “The Definition of the report is invalid” error comes to greet you.
This can be any number of things. In my case an expression was looking for a report variable that did not exist. Once I added the variable Bob was my Uncle. Other causes can include inconsistencies in the report such as problems with dataset and datasource references. Typically if you Preview the report before you deploy you may get a more detailed error that will help diagnose the source of the problem.