Profit and Loss Report error

Hello, clavierwerke. 

Let's do a couple of solutions to help us fix the problem. 

A data integrity issue can cause data damage to your company file. We can use the Verify and Rebuild utility to fix the issue. Before doing the Verify rebuild, as an initial step, updating the QuickBooks Desktop release version is a good start when it comes to fixing issues like you've encountered. 

Then we can proceed to Verify and Rebuild utility. Here's how: 

1. Go to File, then hover on Utilities. 
2. Pick Verify Data.
3. Follow the prompts to proceed with the data verification process.
4. When it's done, go to the Utilities menu again.
5. Select Rebuild Data, then follow the prompts. 

An overview about the Verify and Rebuild process is found here: Verify and Rebuild Data in QuickBooks Desktop.  

After doing the rebuild process, let's go ahead and check the report if its still showing multiple line item credits on invoices.  

Another solution is to run and use QuickBooks Tool Hub and then QuickBooks File Doctor to resolve the issue. This program is a collection of tools that can help resolve major issues that a user might face while working on the QuickBooks Desktop. For the best experience, we recommend using this on Windows 10, 64-bit. Please follow the steps in this article: Fix common problems and errors with the QuickBooks Desktop Tool Hub. 

Keep me updated on how these steps help you. I want to make sure you can get the information you need. Have a great day!

Thanks so much for trying to help. I made sure my Quickbooks was updated, verified and rebuilt the data, downloaded and installed the Tool Hub and ran the QB file doctor. I restarted Windows, opened up QB and the report is still coming up incorrect. :-/

Any other ideas?

It's great that you've tried all possible steps to resolve the issue on your Profit and Loss report, clavierwerke.

Since you're still experiencing the same behavior, it's best to contact our Support Team so they can investigate it further and see what's causing the error.

Here are the steps:

1. Go to Help, then select QuickBooks Desktop Help.
2. Select Contact Us.
3. Enter "P&L report error", select Let's talk and then choose a way to connect.

I added an article on how to customize financial reports for reference: Customize reports in QuickBooks Desktop.

Let me know if there's anything else I can answer for you. I'm always happy to help.