Upgrade os mountain lion to macos sierra

#Upgrade os mountain lion to macos sierra mac os#

Micromat has a version of Tech Tool Pro (I rely on it, along with Onyx) that is 'mostly' compatible with Mojave. I am actually doing the same thing now, although 'backwards'. I used it for testing all my applications for each machine, and it was very helpful. I have a Samsung 500 gig 860 EVO SSD, and had two 'Mojave' partitions on it for each of my Macs. Yeah, I actually did that (via SuperDuper!) when I was testing Mojave.

#Upgrade os mountain lion to macos sierra mac os#

Fortunately, I always keep a copy of the latest full Mac OS Installation file, and I even still have the ones for Sierra and High Sierra. Shoot, I just looked at my Purchased Items in the App Store, and now ALL my prior 'purchases' of various versions of the Mac OS are gone! Was not that way when I was previously running Sierra or High Sierra. Apple has recently been somewhat 'anal' regarding the availability of either of them. Not sure if you can download either Sierra (OS 10.12.6) or High Sierra (OS 10.13.6). You would be taking quite a jump from OS 10.7.5 to OS 10.14.2. The other thing you'll need to do is to insure that any third party (ie, non-Apple) software you are running is compatible with Mojave. Again, this would be downloading the full Mojave OS 10.14.2 file/installer. Your machine can run Mojave, and I would think you could download it from the App Store. But for that, you'll need a backup on an external device. The other way is to do a clean installation of the newer Mac OS.