How to start a business with friends, not to have problems

[mich]

It can be very difficult going into business with friends.  I tried it once on a previous business venture and many challenges and disagreements came up that made it impossible to continue working together. 
We tried several different solutions before we split ways. We differentiated our roles as much as possible to reduce friction and even tried to seek a neutral partner who would help ease the conflicts but in the end we just disagreed on too many of the fundamentals.