From my point of view there are a few think you should look at, to avoid such a situation
– Plan your integration well and look for cultural challenges already in the due diligence phase.
– Have “mixed project teams
– Work together from day – look for the good things of both companies and build the future together. Like this people will feel that they are heard and
not run down. They can also be involved in preparing communication content
– Open, honest and regular communication about what will happen, status and success to avoid rumors and reduce stress levels of the employees