After it updates an entity it crashes. Any good way to follow plugins when they update something.

My problem is that I can't follow what happens. After a plugin tries to update an entity it crashes with the following error "Index was out of range. Must be non-negative and less than the size of the collection." don't think it is important what the error message is but I want to know if there is any good way of following this code. Since I don't know what things triggers on this entity update. I want to find where is error occurrs.

Thanks in advance