Hello, I'm generating a complex regular expression for removing word of textes, but now I get this exception: terminate called after throwing an instance of 'boost ::exception_detail ::clone_impl <boost::exception_detail::error_info_injector<std::runtime_error> >' what(): The complexity of matching the regular expression exceeded predefined bounds. Try refactoring the regular expression to make each choice made by the state machine unambiguous. This exception is thrown to prevent "eternal" matches that take an indefinite period time to locate. Is there a solution to create any removing operation? I have got a vector with strings and I must remove each element on the texts, so I create a regular expression with "or" and case-insensitive search ans use regex_replace to remove the words Thanks Phil