I downloaded Ubuntu 16.04 lts to my mac with double boot. I was able to switch between them easily. However, then I needed to upgrade my OS in my mac partition. When I did that, my mac restarted and booted in Ubuntu. To go back to my mac partition I simply rebooted but the efiboot page did not showed up. There is a disc image that is called Macintosh HD and Recovery HD. Can someone help me to go back to my Mac OSX.
Also when I click to Macintosh HD from Files, it displays an error message:
Unable to access "Macintosh HD" Error mounting /dev/sda2 at /media/emre/Macintosh HD: Command-line `mount -t "hfsplus" -o "uhelper=udisks2,nodev,nosuid" "/dev/sda2" "/media/emre/Macintosh HD"' exited with non-zero exit status 32: mount: wrong fs type, bad option, bad superblock on /dev/sda2, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so.