Hello there, @mpproperties.
I'm here to walk you through the steps in correcting the check numbers in QuickBooks Online.
Let's make sure to enable Custom transaction numbers from the Sales settings so you'll be able to reset the check number sequence. Here's how:
1. Go to the Gear icon and select Account and Settings.
2. Choose the Sales tab.
3. Click Sales form content, then select Custom transaction numbers.
4. Hit Save, then Done to finalize the changes.
Once done, we can create a dummy check for the last number so the future checks will get back to order.
If you're referring to the Bank register that is out of order make sure to sort it by date. Sorting the data by date will show the balance in your register.
For more detailed steps about the process, please click these articles:
Also, you can refer to these helpful articles it provides tips on how to align checks and print sales forms:
Please let me know if you have additional questions about checks, I’ll be here to help. Take care.