Recover GPT Hard Disk files on Windows
GTP isn't the issue, it's the HFS+ (aka Mac OS Extended) volume inside it; in order to read that, you need HFS+ drivers for Windows (or Linux or whatever). Paragon sells a driver for this, or you could use the drivers from Apple's Boot Camp software. I can't vouch for their authenticity, but I found downloads claiming to be just the HFS+ parts of Boot Camp at MacRumors.com and MacBreaker.com.