pdf wont open as it says its pd_

[Lorna5C7F]

When I receive a pdf attachment it wont open and it comes up as pd_  I have been told that my grandchildren have altered a setting on a game that has something to do with sounds. I woudl llove to know how to reset it.

[try67]

If the file's extension is .pd_ then the operating system will not send it to Reader for opening, because it's not an associated extension. You can still open it by dragging and dropping it into the application, but I would recommend just renaming it to .pdf first, then trying again.