Hi, I'm thinking of downgrading back to Mountain lion from Yosemite on my mbp retina 2012 . I have a time machine backup of Mountain lion , can I load the Time Machine backup , and would it install Mountain Lion automatically ?
Yes. Boot into Mountain Lion's recovery mode, and you will see "restore from Time Machine." This will install the OS, and restore all your files and settings.
I haven't personally done this myself, so I am not 100% sure about procedure (whether the HDD has to be erased, etc). Please do a search in the web for thorough information. Or hopefully others will chime in
Hi, I'm thinking of downgrading back to Mountain lion from Yosemite on my mbp retina 2012 . I have a time machine backup of Mountain lion , can I load the Time Machine backup , and would it install Mountain Lion automatically ?
Attach the Time Machine disk then hold the option key when booting and select the Time Machine disk as the boot source. That will take you to a recovery screen. From there use Disk Utility to erase the entire disk to Mac OS Extended (Journaled). Then quit Disk Util and click restore. If Mountain Lion was the OS in use when the last backup was made, that will put Mountain Lion and all your data back on the drive.