Is it possible to install a previous version of OX s Snow Leopard without losing data. I have aMini(late 2012) .

You can't install an older system over a newer one. You would have to back up all your data, then completely erase the disk and then do an install from scratch, restoring your data from the backup.

If your HD is big enough, and not too full, you could partition it and then install SL on the new partition. You could then boot into that; however space is going to be the problem. You could buy an external hard disk - 2TB disks are not that expensive not - and install SL on that. However I don't know whether you can also install Boot Camp on that, though I should have thought so while it is the startup disk. The main problem is that running the system on an external disk is going to be very considerably slower than using the internal one.

Roger Wilmut1 wrote:

If your HD is big enough, and not too full, you could partition it and then install SL on the new partition.

Last I checked, you cannot have multiple OS X partitions if you also have a Windows partition via Boot Camp.

The 2012 Mini can't run anything earlier than Mountain Lion sinceearlier versi0ns do not have the necessary drivers.

Ah - he did say he'd upgraded. It sounds as if he upgraded to a new Mac as well as a new system. In that case he's stuck.

You must be mistaken as to the Mini model. The last Mac Mini to ship with

any version of Snow Leopard was the 2010 model (see chart Mac mini).

If you have upgraded your computer as Roger suspects, then you are

stuck.