UPDATE FOR MAC USERS:
I found a workaround for the failed to patch error!!
Simply use the old 2.7.17.jar version to patch the game; then, navigate to HDOS/RuneLite directory and delete the osbot.jar that the succesful patch generates. Download 2.7.19 and rename it osbot.jar to replace the file you deleted.
When you boot up through Jagex Launcher it should boot to version 19 with your login token intact!