Community
My first suggestion would be to make sure you have the latest service pack. You can find that here.
If that doesn't work I would try right clicking on the black triangle, then click "load printout", then try deleting it. Perhaps it doesn't like to delete an unloaded printout.
In case of such effect you can also trying to send the file to check.
But first of all make sure about updates as suggested above.
---------------------------------------------
If this post answer your question please click "Accept as Solution". It will help everyone to find answer more quickly!