Just installed Zorin 12 and on startup it mounts and opens a number of my other distros on my hard drive. It's mostly annoying but I would like to prevent this from happening. Any way to stop the auto mount??

Using your favorite plain text editor (gedit, pluma, xedit, nano, vim, emacs,....) and with superuser privileges ("sudo su /etc/fstab" will suffice), comment out what you don't want mounted in /etc/fstab with a hashtag at the beginning of the line.

Be careful and don't comment out this distro's root, swap, home, or anything desirable

http://manpages.ubuntu.com/manpages/...5/fstab.5.html

Here's some more info.

. . . or change the settings for the partitions in question from "auto" to "noauto."

See man fstab for more.

Since the question isn't too old, I thought I'd add my 2 cents worth. This problem may have been fixed in free release version 12.2 which I've recently installed on my 64-bit laptop. I have one other linux distro and a Windows distro on my hard drive which don't automatically mount. File manager shows:
+ other locations
in nautilus file manager. If I right click the other partitions the context menu shows "mount". Otherwise you can do a search for disks which will bring up the utility that has a graph of your partition lay out. Select a partition and you can choose the gear icons below "additional partition options" "edit mount options" and turn the slider from "automatic mount options" from "on" to "off". Mine is set to "on" and only affects hot plug thumb drives.