After creating the central file in ProjectWise, opening the file should only temporarily check out the .rvt and .dat files. In this case, the files were staying checked out to the user.
The user was using the wrong program association.
On a machine with the appropriate Revit version installed, and integrated, log into the ProjectWise administrator
In the applications section, browse to the appropriate Revit application and right click-properties
4. Select the browse (...) button for program class name and choose ProjectWise integrated Revit
5. Remove any user assocations the user may have (tools-associations-programs-user assocations in ProjectWise Explorer, right click-unassociate anything under the open action)
1. In ProjectWise Explorer, logged in as the user that will be using Revit
2. Tools-associations-programs- user associations
3. Scroll to the AutoDesk Revit application-open
4. Right click-new association
5. Choose the ProjectWise integrated Revit application