Help please

Help please, how to fix mycareer in game force close (NBA 2k14 PC)

Are you using a roster mod? If so, you might want to contact the person who made it.

nah man i used new MC that i made but i modify with red MC

In that case, that's quite likely the cause. Either the file is corrupted, or the changes have resulted in an inconsistency/conflict in the data that's causing a crash.

can you give me a tutor to fix it? please

Without knowing what you changed with RED MC, I can't suggest anything specific beyond undoing those changes, i.e. changing the values back to what they were before. If that doesn't fix the problem, then your only option is to restore from a backup if you have one, or start over.

Only changed my player cf with cf giannis tjat i downloaded from Facebook and i trade my player with pau gasol from cavs to lakers.

My guess is that trading your player has resulted in some conflicting/incorrect values that are causing a crash. Again my advice would be to undo the changes you've made and restore the values to exactly what they were before, and see if that resolves the crash. If not, you might need to start over, unless you have a recent backup of the save file before you made those changes.