Usually when I go to "Restart into Mac OS X" from Boot Camp's system tray icon it works fine, but just recently it has started giving me this error and not working. It seems like usually when this errors hows it's because the Mac volume is bad or missing, but I have a perfectly working HFS+ boot volume that is visible in Windows and boots just fine. I do also have a second HFS+ partition for data, but no problems with them. Any ideas?