I updated a project to "Completed" and now have to make some changes to that project's transactions. However, the project no longer appears in the project list.

I'm here to help you locate your completed projects so you can make changes easily, Fernando.

Once you update your project, normally it'll show on the project lists page. We can review your status to ensure that it is filter correctly. Let me show you how:

1. Go to Projects.
2. Change the Status to All statuses.
3. Check the status column to verify if it's Completed or In progress.

I also added a screenshot for your visual reference.

In addition, you can check out this article if you want to learn how to get the most out of your financial report: Customize reports in QuickBooks Online.

If you have additional concerns about managing your projects in QuickBooks Online. Feel free to come back to this thread, the Community is here to assist you.