If the scheduling mode is not closed correctly by either clicking Save or Cancel, this can cause a lock to form which will stop all project members from adding, removing or amending task and milestones.
To clear this lock go the specific project and click on the dropdown arrow next to Add Milestone, select Clear Gantt Lock.
Caution
- If any project members are still within the scheduling mode when the Clear Gantt Lock is used all unsaved changes will be lost. You can click on the padlock against a locked task or milestone to see who is in the scheduling function.