If you bill 100% of the contract amount for a project and the rule Mark projects completed when billed 100% is checked in Settings > Billing & Invoices > General, the project status changes to Completed and the project is no longer visible in the Projects screen. Similarly, if you manually change the status of a project to something other than Active, say Inactive, then the project is no longer be visible in the Projects screen. You must first apply the Project Status filter to see the inactive projects and then change their status to active. To do so:

1. Open the Projects screen and click the Filters icon.
2. Select the Project Status filter and choose Inactive.
3. Apply the filter. Check Apply Filters for details.
4. You can now see all your inactive projects in the list. Select the ones you want to make active again and click Actions > Batch Update.
5. Change the Project Status to active and save your changes.

These projects disappear from the inactive list and reappear in the list view.