Once you initiate the sync the items will be loaded and processed in sequence. This can happen in a matter of minutes or may take hours, depending on how much data is in the customer's system. You must have QuickBooks Web Connector configured and enabled to run and your computer must remain online and connected to the internet for the data synchronization to occur.
If you are concerned that data has not transferred between the systems you may open the Web Connector panel and choose to update the data manually. During the synchronization the progress bar may move slowly - this is completely normal as there may be a large amount of data to transfer and it is dependent on your internet connection speed. Please allow the transfer to proceed without interruption as this will help ensure that data is synchronized successfully without errors.