For a transaction to move to ‘completed’, it must have:

• a business category assigned to it (if it has been assigned an old category, you’ll see a message telling you to update it)
• an attachment - a receipt if it’s an expense or an invoice if it is income
• A VAT amount (if you’re VAT registered and use the cash accounting VAT scheme)

While you’re there, you should also make sure the ‘allowable tax amount’ for income tax purposes is correct, and that the transaction is categorised correctly.