Error: You and another user were working on this at the same time. Another user finished before you did, so your work was not saved. Why- I am the only user?

Check your audit log. Do you see anything?

Let me route you to the best help available who can assist you fix the error you've encountered, CJBil.

We previously had an investigation about the error, which was marked as closed and resolved. Since you're still experiencing the issue, I recommend reporting it to our Customer Care team for deeper evaluation. To do this, here's how:

1. Sign in to your QBO company.
2. Go to the Help (?) menu.
3. Select the Search tab and enter a brief description of your concern in the provided field. 
4. Press the Enter key.
5. Click the Contact Us button.
6. Choose a way to connect (Callback or Chat ).

Additionally, you can personalize your sales forms with the new version of invoicing and estimates in QuickBooks Online (QBO). If you need a guide on how to do this, you can check out this article: Customize invoices, estimates, and sales receipts in QuickBooks Online.

I'll be here in the Community if you have other concerns about managing your business' growth and transactions in QuickBooks. Please don't hesitate to leave a reply below, and I'll gladly help.