Can I delete the paystub which is not processed?

I'm here to help you resolve your payroll check issues in QuickBooks Online, nirvanaenterpris.

Yes, you can delete the unprocessed paycheck. Let me guide you with these steps:

Since you're unable to delete one, it's possible that you've created a new paycheck. With this, you'll have to remove the most recent paycheck before you can delete the old one. Here's how:

1. From the Payroll tab, select Employees.
2. Click Paycheck List under Run Payroll.
3. Change the date range and then choose the paycheck you want to delete.
4. Click Delete.
5. Mark the checkmark box to confirm the deletion and click Delete Paycheck.

Once deleted, the system will automatically  recalculate your tax liabilities. You can refer to this article for more information: Resolve a tax overpayment.

Let me know if there's anything that I can help about paycheck. Keep safe!