You have a project where the task status can be updated however in other projects, the task status can not be updated. It is read-only.
Release : All Supported Releases
This is determined by which % Complete Calculation Methods is set for each project
How the % Complete is updated depends on the % Complete Calculation Method on the project
Once the % Complete is updated on the project, the status of the task on the Project will update based on that percentage:
Note: Even if the % Complete Calculation Method of the project is set to Manual, in order to be able to save a task status of Completed, there must be 0 ETCs on the task.