Revit Transparency pixelated

[JonClarke_hA]

We are running Revit Architecture 2013 at my firm and one of the computers was having an issue with 3d views not showing up when printing.  We did a repair and it fixed the problem.  But when we repaired, we got a new issue where materials with transparency showed very pixelated (see attached Image).  This error occurs on the screen and when the image is printed.  I opened the file on another computer and the 3d view looked correct.

We tried reinstalling the materials library but that did not fix the problem.

Can anybody suggest a fix for me?

Thanks!