Can I dual boot 10.6.3 with Mac OS Sierra already installed?

  • Asked about:  Mac OS X 10.6 Snow Leopard

1 Answer from the Community

  • Answer

    Maybe yes, maybe no.

    OS 10.6 will likely not "install" on newer Macs, especially Macs purchased from Apple with more recent versions of OS X pre-installed. However OS 10.6 may "run" on newer Macs.

    For example, I purchased a refurbished 2011 iMac with OS 10.8 pre-installed. The Mac would not allow OS 10.6 to be installed. However, when I installed OS 10.6 on a small partition on an older iMac and then made a disk image (DMG) of that partition, I could put the expanded image on a partition of the refurbished Mac and OS 10.6 runs without any issues.

    Here is a suggestion. With an external drive (HD or USB Flash drive) reformat as "Mac OS Extended (Journaled)" with GUID partitioning option (I think newer Disk Utility automatically puts the GUID partitioning in, older Disk Utility has it as an option). Then on older Mac install OS 10.6 to that external partition. Restart that Mac, hold OPTION key during startup, and select the external partition. You should now be in OS 10.6. Do system update to bring it up to OS 10.6.8. Then connect external drive to your Mac. Again, hold OPTION key when starting Mac and choose the external partition to start up from. If successful, you will now be running OS 10.6 on your Mac.