How do I enter a previous payroll check into my register without my salaries total being wrong? I entered previous payroll into QB at set up.

Hello there, momsanmore.

I'm glad you've reached out to us. Let help provide some information on how to enter your previous payroll check into register in QuickBooks Online (QBO). 

You can manually enter your employee's payroll information if you haven't run payroll transactions after the payroll set up. Here's how to get started:

1. Click Workers from the left navigation panel.
2. Go to the Employees tab.
3. Click the Employee name.
4. Click on Enter 2018 prior pay details. 
5. Please be reminded that you need to enter your employee's pay schedule and pay rate before you get this option.
6. Complete all the employee interview.
7. Click Done.

For additional reference, you can check this article on how to set up a prior payroll. 

If you already run your first payroll and can no longer access these options, I encourage you to get in touch with our QuickBooks Online Support Team. They have the tools to do a screen share and record your Year-To-Date (YTD) payroll. 

Here's how you can contact our payroll support: 

1. Click this link: https://payroll.intuit.com/support/contact/?infosrc=qs&service=64.
2. Select your payroll subscription.
3. Choose Payroll for the topic.
4. Click View Contact Info to get the phone number. 

Please know that I'm just a post away if you have other questions about QuickBooks Payroll. Wishing you continued success.