Here is a simple maxscript that works with instanced objects. While working with Maxwell, I always have problems with instanced light meshes. So, I thought writing a script for this job would be fine.
Just select some objects from the scene. Script checks every one of them, finds instances and makes them unique. As this is a macroscript, you need to add it to a quad menu, a toolbar or a menu. You can find the script in category “emrahgunduz.com”, named as “DeInstance”.