Hello, I've been playing around with Xpressive and have hit a stumbling block when working with Unicode. I really am not sure if what I am trying to do is possible and that I'm just doing something silly wrong. Here is a very small example- wstring in = L"A ЏиϊсoδΣ Hello //World"; wsregex comments = wsregex::compile(L"(//[^\\n]*|/\\*.*?\\*/)"); wstring clear(L""); wstring out = regex_replace(in, comments, clear); (Note if the wstring 'in' gets scrambled in email I have attached a tiny UTF-8 encoded file of what it should contain.) This code compiles but after executing the wstring 'out' only contains "A ". If there are no Unicode characters in 'in' then the regex replacement works as expected. Kind regards, Eóin. "A ЏиϊсoδΣ Hello //World"