User is trying to run the Budget Comparison report, but cannot see any data in the Spent section.
For this report to reflect accurate data, make sure you have actually used the same set of employees, activities and expenses in your project's time and expenses as you had specified in the budget. Otherwise, the report does not serve its purpose. To ensure that you only use the budgeted items on a project, you can use the project rules that restrict the project to budgeted items. Check out this article for details: Using budgets to limit employees, activities and expenses on projects.