Hello, Mathias! First of all, big thanks for updating searching in binaries in v. 3.1. It seems to me that it works. I started to use it heavily and realized that I don't know how to properly use regex searching in mc. Some constructions that I regulary use in other applications don't work here. For example, nor /s nor [:space:] don\t work as class of "space" characters; lookahead and lookbehind: (?=), (?!), (?<=), (?<!); possessive quantifier: ++ (but it seems *+ and lazy versions *? +? work); backreferencing causes mc to hang at all (i am searching "(a)\1" in folder with one plain text file, which contains "aa"), so I have to close it through task manager. Could you provide some information about syntax of regex mechanism using by mc?