the only way i can think of is painful but is the same as anyone else having any problems with any EP, gameplay or whatever really
remove the downloads folder to the desktop
see if you can enter lots ok without it
for hacks....check with the relative creators about what works and what doesn't and update as necessary, or availability, and only use stuff they say is compatable
if you aren't sure either test each one individually yourself or leave it out of the game
for custom content...ensure you have the relevant meshes and recolours and the current
CEP installed
enable custom content and exit the game. then reload the game to activate the content
test the lots...if there is a problem remove d/load folder and batch test the items till you find the culprits
leave out custom careers till you have checked for compatability