Circular reference causing stack overflow with Automapper

In your Automapper configuration:

Mapper.Map<OrderLine, OrderLineDTO>()
    .ForMember(m => m.Order, opt => opt.Ignore());

Mapper.Map<Order, OrderDTO>()
    .AfterMap((src, dest) => { 
         foreach(var i in dest.OrderLines) 
             i.Order = dest;
         });

I was having the same issue and solved it by downgrading to version 4.2.1. apparently the checks for circular references was expensive so they made it default to not check. Migrating to AutoMapper 5 - Circular references

Supposedly these are supposed to be the settings methods for v 5+ but it didn't work for my data model because we opt'd for complex dto relationships instead of single use dtos for each action.

// Self-referential mapping
cfg.CreateMap<Category, CategoryDto>().MaxDepth(3);

// Circular references between users and groups
cfg.CreateMap<User, UserDto>().PreserveReferences();

http://docs.automapper.org/en/stable/5.0-Upgrade-Guide.html#circular-references

Automapper is supposed to be able to statically determine if the circular reference settings in v6.1+, So if it doesn't work for you automatically in version v6.1+ contact the automapper team.

I was having the same issue using EF 6 and AutoMapper 6. Apparently what Kenny Lucero posted led me to the solution. Here's an extract from AM site:

// Circular references between users and groups
cfg.CreateMap<User, UserDto>().PreserveReferences();

Adding PreserveReferences() to both models made it work.