Most users delete or make the accounts inactive (that are no longer required) to keep the chart of accounts organized. After making the accounts inactive, the account disappears from the lists, however, QuickBooks keeps the older transactions on the report. There can be instances when you may need these inactive accounts back to the list. In such a scenario, you make the inactive account active again. To find the best information for the same, you can read here how to activate an inactive account in QuickBooks Online and QuickBooks Desktop.