After Project Server 2007 to Project Server 2013 migration we were unable to edit the Quick Launch. The ribbon were completely grayed out.
We resolved this issue using below steps.
1.Click on “Edit Links”
2.You will get below error message.
3.Click on OK. You will find that “Ribbon” is grayed and you wont be able to save any changes.
4. Refresh the IE page. After Refresh you will find “Save & Close” button as enabled on the ribbon.
5. Make any small change in the Quick Launch like enable or disable any of the link.
6. Click on Save and Close
7. Your changes will be saved and next time you wont receive error while accessing the Quick Launch link.