Transferring a saved game from one xbox profile to another?

Hard to say... Go to the memory part of your console and see what's there before deleting anything, (on the corrupted profile). Then go to your M Effect character and play the game to see if that hasn't corrupted. If not then get a usb (this may be longer, but only way I know) transfer the ME files onto it, sign out of that account, go to your new account and add on the ME data, play to see if it works then delete old data. If this doesn't work, I'm sorry, I'm just using knowledge from what I know that I've done in the past(It worked)