With every iteration of data migration, you need to get progressively better. To achieve this, data validation needs to be a well-documented repeatable process and needs to start early on. Do not wait until the deployment stage to engage the business. Here are a few tips to make this process smoother:
Define validation test cases for both the business and IT validation.
IT validation: This generally includes verifying record counts, totals, and referential integrity by running tools such as Consistency check (Consistency check is a tool available in Dynamics AX. It validates and fixes referential integrity issues. It can be found in System Administration module, periodic section). You need to acquire different types of validation scripts; it is a good idea to have scripts for validating extracts, if there was an issue in extraction, you can catch it sooner in the process.
Business validation: The business owns the data, and it is critical to have the business involved to start...