How do you resolve payroll mapping errors for past transactions when an error prevents certain dates from processing?

I've got you covered, @No_way.

You can consider deleting and recreating the paychecks to resolve the issue. Here's how:

1. Sign in to your QuickBooks Online (QBO) account.
2. Click Payroll from the left menu, then select Employee.
3. Select the paycheck you want to delete and click Delete.
4. Choose the I understand that this action cannot be undone checkbox.
5. Click Delete Paycheck to confirm.
6. Once done, you can now recreate the paycheck. 

However, if you can no longer recreate the paycheck, you'll need to set up a prior payroll. For more guidance, feel free to check out this article: Set up a prior payroll for QuickBooks Online Payroll.

If you're having difficulties following the steps, I suggest reaching out to our QuickBooks Payroll Support Team. This way, they can guide you with the steps through screen sharing.

Our doors are always open to help you again if you have any other concerns or follow-up questions about payroll mapping. Have a great day ahead.

I tried to reach out to Support, and the "Community" was the only option...

We're talking about transactions back to 2015. So, unfortunately, recreating payroll isn't an option. It allowed me to change categories and update everything, and something went terribly wrong - I've narrowed the errors down to just the S-Corp Health and employee medical insurance accts as the culprits. When I tried to fix it, that's when I get the error that I need to "try again later." I've been trying for over 10 days. The dates I have been able to correct resolved all of the issues, but now I have sporadic dates that still have the miscategorized payrolls - something I can't fix. Incredibly frustrating. 

I know how you want to get this fixed and I'm here to provide you some information as to when you can contact our support, No_way.

Our payroll support team is available Mondays to Fridays from 6 AM - 6 PM. That's the reason you're only seeing the Community as an option. You can contact them again to check if you'll be able to request payroll correction. To do this, you can follow the steps provided by @Mark_R.

If they're unable to do a correction, you can create a Journal Entry if this is only for reporting purposes. To do this, follow the steps below.

1. Select + New.
2. Select Journal entry.
3. On the first line, select an account from the Account field. Depending on if you need to debit or credit the account, enter the amount in the correct column.
4. On the next line, select the other account you're moving money to or from. Depending on if you entered a debit or credit on the first line, enter the same amount in the opposite column.
5. Check the amounts - you should have the same amount in the Credit column on one line and the Debit column on the other. This means the accounts are in balance.
6. Enter information in the memo section so you know why you made the journal entry.
7. Click Save and new or Save and close
   
   

For your reference, you can run reports in QuickBooks Online to get the information you need: Run reports in QuickBooks Online.

Let me know if you need anything else with your payroll. We'll always be right here to help.