After choosing all transactions, and get 0.00$ when doing bank reconciliation, can we delete other transaction which are not chosen?

Hi there, 

Good job on starting the reconciliation process in QBO. I'll be happy to share more information about this. 

QuickBooks Online allows you to delete any unwanted transactions and I'll show you how. First, it's important to note that when you delete, you permanently erase a transaction and its trace from your books. The only place you can check some details of a deleted transaction is on the Audit Log. There are some transactions that you can’t void, such as estimates, bills, deposits, supplier credit, purchase orders, delayed charges, and delayed credits. But you can delete all types of transactions. Here's how: 

Void or delete transactions

1.    Find and open the transaction.
2.    Select More, and then Void or Delete.Note: For some transactions, just select Delete.
3.    Select Yes to confirm your action.                              

If you had to delete or void a previously reconciled transaction, find out how to bring your reconciliation back to balance. I highly recommend reaching out to your accountant if it's okay to delete the transactions in order to avoid any discrepancies in the future. Otherwise, feel free to ask questions. I'll be on standby. :)