Height poly mesh can not get into edit mode

welcome I modeled a mesh and applied array modifier after that. now I can not get into edit mode. what should I do. became very height poly and I can not make use of decimate modifier.

if its so high poly that you cant even go into edit mode, then i suggest you look into retopology. a model should never be that hi poly no matter what, unless you are dealing with very detailed displacement stuff.