This issue generally indicates that there are tasks that are not set up for the Content Editor role that would allow them to save the content.

To enable the tasks allowing Content Editors to save content:
  1. Start from the Core persona
  2. Navigate to Security > Roles
  3. Click on the Content Editor role
  4. Under Roles to the left, click Tasks
  5. Click the Edit button to the upper right
  6. Check the boxes next to each task labelled as Audio/Video Content, Content Engine, or Content Groups (labels are to the far right of the task)
  7. Click the Save & Exit button