The #1 reason joint ventures fail is the same reason that business partnerships fail. The problem is that joint venture partners don’t think of their venture as a business, but it is.
Business is about relationships that require open, honest and comprehensive discussion and decision making. The decisions need to be written into a partnership or joint venture agreement.
Not having a written agreement creates space for misunderstandings, forgetfulness and ill will leading to failure. The price for these breakups is high, not only financially, but personally.
There are those who will tell you that you don’t need a written agreement in a joint venture because it is limited in size and time, but my experience as the rescuer of partnerships has shown me very strong evidence to the contrary.