How to prevent second OS X partition from seeing apps in the other partition? I have two partitions set up on my MacBook and I'm having issues when installing software on the new partition as it says it is already installed. The application is installed on the other partition but should not be recognised by the new partition.

Is there a way to disable that partitions ability to see the apps etc. from the original partition?
Unmounting the 'unwanted' partition before installing the new application should help in most cases:


Quit all open applications
Start Terminal.app and enter diskutil list


output looks like this:  

 #: TYPE NAME SIZE IDENTIFIER
 0: GUID_partition_scheme *121.3 GB disk0
 1: EFI 209.7 MB disk0s1
 2: Apple_HFS Yosemite 60.2 GB disk0s2
 3: Apple_HFS Mavericks 60.3 GB disk0s3
 4: Apple_Boot Recovery HD 650.0 MB disk0s4  



determine the identifier of the partition to unmount by size/volume name and enter diskutil unmount /dev/IDENTIFIER
(in the above case diskutil unmount /dev/disk0s2 to unmount the 'Yosemite' partition)
To remount this partition afterwards just enter diskutil mount /dev/disk0s2