Hi
Can you tell us more about culture conditions? Bellows are well known conditions to solve the problem.
1 Lower the temperature after induction, try 25 degree or 16 degree after induction and harvest after O/N culture.
2 If you use IPTG for induction try lower concentration such as 0.1 or 0.01 m M.
3 Attach solubility tags to your protein of interest such as GST, MBP, SUMO, GB1.
4 Coexpression of protein chaperone such as GroEL.
Those are the strategy I actually tried and all of them showed some effect on protein precipitation.
Good luck!