Right click on 'Major Projects' and click Create button in right-click menu.
Enter "56M" into the Name field and click 'Create'
As you can see, the system won't allow this, however if you change this to something new like "57M" the system will allow it, because it has never been used before. Assume this is something to do with the delete flag against the record.
Hi Andrew,
This error occurs if a project type has already previously been created under the same name and then deleted.