1) While accepting payment via cheque, please click on the hold cheque option as shown below and accept payment. 

2) To unhold cheque please click on money manger. Navigate to Deposit and reconcile and click on unhold cheques. 

A > Click on money manager.

B > Deposit and reconcile.

C > Unhold checks.

3) Select the cheques to be unhold and click on Unhold Cheques.