When trying to save a project back from MSP (Microsoft Project) to PPM, receive a Project Save Failed error.
Prior to the project save failed message, receive message <task> in <Project Name> cannot be completed in the time allocated because there is a scheduling conflict between this task and another one to which it is linked".
One reason this happen is if a Summary task on the project is manually scheduled and any of its subtasks' Start / Finish dates fall outside the range of the summary task. Note: Even if summary tasks are set as auto scheduled, if you manually change the start date, finish date, or duration of the summary task, it will change the summary task to manually scheduled. This is because Summary tasks that are auto scheduled dates/duration are calculated based on the child tasks under it, so if you manually change a summary task date or duration, MSP looks at this behavior as being that of a manually scheduled summary task instead of a auto scheduled summary task. This issue can also happen if you set a date of a different task, and drag the date cell to tasks that include the summary task.