I have no idea how to fix it. I probably do not understand the manipulation with BackedInfo structures fully. It is obious that it is caused by doing a search from the modrdn operation callback memberof_res_modrdn() which is set up in memberof_op_modrdn(). Other backends does not call any backend operation at the same moment (op->callback). Frontend fe_op_search() is called. It tries to choose the right backend with select_backend(). Which returns the overlay backend (bi_type == "over"), over_op_walk() then selects fe_op_search() again, and we are looping infinitely. I have no clue how to hide or temporarily deactivate the overlay in memberof_res_modrdn() to make the select_backend() function to choose the right underlaying backend. Or maybe I have choosen a wrong way of fixing it. All ideas are welcomed. :-) Thanks & Regards, Jan