> Please check the archives, before posting; this has already been asked I'm really sorry, I did try. This is the first time I've ever done anything other than 'just use' mingw32. I rummaged around various website, http://www.mingw.org/, https://osdn.net/projects/mingw, etc, entering 'vsnprintf' in various search boxes. After your prompt I downloaded the Gzip'd Text of the archive, and searched that. But this seems somewhat clunky and I can't help but feel I'm doing something wrong! Hopefully I'll never have another issue. > it's a bug in mingwrt-5.2.2 So I did 'mingw-get upgrade mingwrt=5.2.1' and that seems to have got us going again. I think this probably simpler than applying the patch but if we have any more problems I'll try it. Your help is much appreciated, thanks, Matt