Default OTA failure (SOLVED, thanks to @nkk71)

hi all, i have a Taiwan HTC One with 4.2.2 and software version 2.24.709.1 , s off, unrooted and stock ROM . I receive 4.3 OTA update when i check for software updates, and it downloads fine too but whenever i try to install it and the phone boots up into stock recovery, the progress bar goes halfway and then the recovery shows a red triangle and i have to hard reset the phone. i'm running stock recovery, everything is stock but i have s off and unlocked bootloader, which shouldnt be what's causing this problem, anybody got any suggestions? thanks