You must clear audit errors before changing the Budget status to Complete. Please go INTO the Budget document and then click Data Validation to expose budget-related validation errors preventing Completion of the budget. One common budget error that is easy to clear is the allocation of funds within Institutional Commitments. To resolve this, simply navigate to either or both the Cost Sharing and/or Unrecovered F&A panels and Save. The allocation should automatically refresh, and if it requires any adjustment, you can manage that onscreen prior to the save.