The terms ‘check in’ and ‘check out’ apply to Enterprise projects, Enterprise resources, and to the Enterprise Global template. A user must check out any of these before editing, so that others have Read-Only access, until the user checks them back in. Check out occurs on a first-come first-served basis, so the first person who opens the project for editing, checks out the project.
First of all, sign into URL, as shown below.
Enter your credentials to login into Office365 Project site. After successful login, you will able to see the screen given below as a landing page.
Now, click on the Menu, as shown below.
Upon clicking on the menu, a list of items will be displayed, as shown below.
Select Project.
When you click on Project, you can see Project online landing page, which is PWA (Project Web App) site, as shown below.
Click on the settings gear, as shown below.
Select PWA settings option from dropdown. Subsequently, the page navigates to PWA Settings landing page, as shown below
From Queue and Database Administration, select Force Check-in Enterprise Objects.
On clicking on Force Check in Enterprise objects links, you will find a new page with the list of Projects, which are checked out to others earlier. Kindly refer to the screenshot given below for more understanding.
In my site, I have only one project, which is checked out to prem at 4/12/2016 time.
Now, our task is to force check in. Select the check box beside Project name.
Click on check in button and the target is accomplished.