Hello, Sarah. 

I'm here to help you ensure your checks are printed with the correct check numbers. 

Just to give an overview, we won't be able to edit the check number if the Print later box is checked. This is why you're unable to enter or edit the check number. 

Regarding the "check number already in use" prompt, we can still proceed to print the check with the same number by clicking on Continue. Though, this will duplicate the number from a prior check. 

So, we'll want to edit the previous checks you've already printed with the correct numbers and sync it with your actual check. Here's how to do it: 

1. Go to Expenses. 
2. Find the "Bill Payment (Check)" transactions and open one. 
3. Edit the number under Ref No. If the box is greyed out, make sure to uncheck the Print later box. 
4. Once done, click Save and close. 

Do this until all of the recorded and printed checks have the correct numbers. 

Now, we can print the current checks by going to the + New button, then selecting Print checks. Make sure to enter the correct beginning check number in the Starting check no. box.

The system will automatically increment the number by one. So if you have three checks in the queue, it will print as "Check no. 1", "Check no. 2", and so on. 

For more details about printing checks and setting up your print settings, we can take a look at these articles: 

• Print a check in QuickBooks Online
• Configure your print settings for printing checks in QuickBooks Online
• Print a report in check number order

Need to check your financial data after printing your checks with the correct numbers? We'll want to browse an article in our Financial Reports topic page. They'll contain guides on what reports you can run and how to customize it. 

Do you have other concerns regarding your checks? Or perhaps do you need help with other entries? Keep me in the loop in this thread, and I'll help you out.