Installing OS X on 2 Partitions - Can malware spread between partitions? Cons?

[mrtemp]

I wish to purchase an iMac to share with my son. Can I split the hard drive into 2 partitions and install OS X 10.11 on each partition?

I want to ensure that doing this essentially makes it into 2 separate computers and that if one partition got malware or a virus it could not move to the other partition? Also, if my son downloads a 30-day trial version of a software program on his partition, can I still install it on my partition at any time after his trial runs up?

Are there any cons or special software needed to do this?

 

[Gregg2]

It might be easier to have two user accounts.

 

[BrianBaughn]

Two admin accounts wouldn't protect in the way that the OP wants.

My guess is that you couldn't be sure if both partitions are mounted although I've never heard of a particular case like this. I think there's a way you could prevent the inactive partition from mounting at startup, though.

As to software trials...there are multiple ways for software to determine the trial usage record. So the answer is probably, "It depends."

 

[KALLT]

It is not possible to prevent mounting of a partition if you have absolute control over the machine. In theory, malware could attempt to mount any drives it finds and infect those too. Might be something a future ransomware would do.

You’d have to encrypt both partitions with FileVault, without storing the encryption password of one with the other. You’d also have to maintain two separate backups.

Other cons: lots of space wasted and you have to reboot to switch users.

I’d consider a good backup strategy instead and maybe a standard account for your son. A lot of software doesn't need to be installed in the system-wide /Applications directory. Each user can have their own ~/Applications directory and drag & drop apps into it. You should give this a try first.

 

[FreemanW]

A couple of questions.

First, why the desire to install an out-of-date Operating System? That is simply itching for a fight.

Second, why not simply create a second user account, and even employ parental controls on that account?

Additional points for creating a bootable external hard disk drive, USB 3.0, from which the child can boot the iMac and use. It will be slow enough that he won't be using the iMac at all. Problem solved. ;-)

 

[mrtemp]

A couple of questions.

First, why the desire to install an out-of-date Operating System? That is simply itching for a fight.

Second, why not simply create a second user account, and even employ parental controls on that account?

Additional points for creating a bootable external hard disk drive, USB 3.0, from which the child can boot the iMac and use. It will be slow enough that he won't be using the iMac at all. Problem solved. ;-)

That was a typo, I meant 10.12.

This is for my adult son, LOL. But my reasoning for not creating a second user account is to keep everything completely 100% separate. When a new app is installed, I want it only on the one account. He does web design stuff and installs older browsers, etc. and I don't want that stuff on my side. Another big concern is malware, my understanding is that if I keep 2 partitions, malware won't screw up my side?

 

[BrianBaughn]

Not knowing the capabilities of current or future malware I'd say there's no guarantee a separate partition, even if it's not mounted, would protect you.

 

[FreemanW]

Okay.

So my first and last thought on the matter.

It's a grand idea . . . . but, an iMac with a Fusion drive makes it doubtful (impossible?) for my money, which leaves you with trying (certainly no guarantees . . . and probably just as impossible) it on a large SSD or . . . . . . . . . . . . the option of an external bootable drive remains; where the internal volume does not get 'mounted' but instead, the external USB 3 or Thunderbolt drive is the mounted and working volume.

I suspect that performance would be unacceptably kludgy.

 

[KALLT]

This is for my adult son, LOL. But my reasoning for not creating a second user account is to keep everything completely 100% separate. When a new app is installed, I want it only on the one account. He does web design stuff and installs older browsers, etc. and I don't want that stuff on my side. Another big concern is malware, my understanding is that if I keep 2 partitions, malware won't screw up my side?

As I said above, use a standard account. In a normal macOS installation, standard users can only write in their own user directory as well as in a handful of other non-essential locations. They can't install programs in the shared /Applications directory either.

In many cases, software can be installed in the user directory too. All you need to do is create a folder called "Applications" in there. Then instead of copying your apps into /Applications, you use this one. From your own user account, you won’t even know which software is installed in your son’s account. If you want to share software, then all you need to do is move it to the shared /Applications directory.

 

[Gregg2]

You can have apps in your User Account's Applications folder (Users/YourAccount/Applications) that would not be present for the other User. Apps you want to share should go in the Users/Applications folder.