I paid two salary payments in error and repaid one payment, how do i post the correction

Hi mand1, thanks for joining the QuickBooks Community 🙂

If you paid and were refunded for the duplicate payment on the same day, it's easier to simply exclude these transactions from your bank feed in QuickBooks. You can do this by ticking the check-box to the left of the transaction(s) in the for review tab > scroll to the top of the page and click exclude.

If you'd prefer to record the transaction in your books, you would first create the employee as a supplier in QuickBooks. You can then record the outgoing payment with an expense (+ New > Expense), selecting the date that this was paid, the payment account, the relevant wages (or other expense) account under 'category' and the total amount. You can then match this to the outgoing payment in your bank if you have this connected. 

After this, you can record the repayment by following the steps for a supplier refund:

1. Create a supplier credit (+ New > supplier credit​)
2. Choose the correct date and supplier, enter the same wages (or other expense) account used above and amount 
3. Click on + New > Bank Deposit (to show that the money went into your bank account)
4. Choose the correct bank account on the top left corner, choose the date when the money actually hit your account
5. Scroll to 'add funds to this despot' - set the 'Amounts are' to 'No VAT'; for 'received from' choose the correct supplier, for the account choose Creditors, enter the amount & save
6. Go to the suppliers page and select New transaction > Cheque

7. On the cheque, tick the supplier credit against the bank deposit - the total will now show as zero. Save & close. 
8. Return to your bank to match the deposit against the refunded payment