Upgrading Mac mini, late 2014 from OS X Yosemite v. 10.10.5

ANY USB drive will work with Time Machine to backup your MM. I would recommend that you look at the https://eshop.macsales.com/shop/owc-mercury-elite-pro. With most off the shelf EHD's they may simply needed to be formatted to work with Mac OS. Most come pre-formatted for MS Windows use. If you are not familiar with Time Machine please click Back up your Mac with Time Machine

The last version of Mac OS a 2014 Mac mini can run is Catalina. Please note below what Apple prints:

macOS 10.15 Catalina compatibility

Catalina arrived in October 2019, and the latest version is macOS 10.15.7with Security Update 2022-05 (which arrived in July 2022) and can run on the following Macs:

• MacBook (2015 to 2017)
• MacBook Air (Mid-2012 to 2019)
• MacBook Pro (Mid-2012 to 2019)
• Mac mini (Late 2012 to late-2018)
• iMac (Late 2012 to 2019)
• iMac Pro (all models)
• Mac Pro models from 2013

If you want to upgrade to Catalina click the Apple symbol in the upper left of the display and there should be something for updates under there. As all of my machines are we'll past Catalina and the process has Update process has changed over the years otherwise I would be be more specific.

You can upgrade a Mac mini (Late 2014) to Monterey – and no further.

Unfortunately, Yosemite is old enough that it may not be able to access modern https sites, and it also might have trouble accessing the App Store. I think you're going to need to upgrade the OS in stages.

Step 1: Back up your Mac.

Step 2: Upgrade to Sierra

Using a modern Mac or PC, download the .DMG file containing the Sierra installer to a USB drive of some sort. This will not create a bootable installer; just a drive with a data file on it. If this is a Mac-formatted drive, use HFS+ (Mac OS Extended) format instead of APFS – Yosemite predates APFS and won't be able to make heads or tails out of it.

How to download and install macOS - Apple Support

Transfer the USB drive to the old Mac and copy the .DMG file to the old Mac. Eject and unplug the USB drive. Open (double-click) the .DMG file to mount the disk image. Run the Sierra installer inside.

Note that the old Mac needs to be running some version of the Mac operating system, or it won't be able to use the .DMG file. The point of involving the modern Mac or PC is simply to get around the problem that Yosemite's version of Safari might not be able to negotiate a https connection to the Apple Support page.

If this succeeds, your Mac will be running versions of Safari and the App Store that likely will be recent enough to be able to access Apple Support articles and the App Store.

Step 3: Upgrade to a higher version of macOS.

You could try to do this in one jump (Sierra -> Monterey), or in stages (Sierra -> Catalina -> Monterey).

Note that Catalina and later break 32-bit applications, and get rid of iTunes in favor of separate applications (Music, TV, Podcasts, Books, and Finder-based iPod/iPhone/iPad management).

As far as saving your data, I would suggest getting an external drive (or drives), and making at least one full backup of your Late 2014 Mac mini before doing anything.

This can be a Time Machine backup, or a clone backup made with Carbon Copy Cloner or SuperDuper! The current versions of Carbon Copy Cloner and SuperDuper! require something better than Yosemite – but you can still get an old version of either that is compatible with Yosemite.

Once you have a backup on an external drive, you would be in better shape to transfer your data to a current Mac – even though the OS itself would not transfer, and some of your applications might not still run.

IronFilings wrote:

I did some research and found an article in MacWorld By Karen Hallam, dated 9/26/23 that discusses which version of Mac OS is compatible with your device. In it she says that Mac OS X Yosemite v. 10.10.5 is the latest version that will run on mini models from early 2009 to 2012. I believe my mini has been mislabeled as a late 2014 model, and is instead an earlier one. The processor is a 2.6 gigahertz Intel core i5.

I am surprised that MacWorld would publish such a flawed and misleading article. As per MacTracker (which is usually accurate),

• The Early 2009 and Late 2009 Mac minis can run El Capitan.
• The Mid 2010 and Mid 2011 Mac minis can run High Sierra.
• The Late 2012 Mac minis can run Catalina.

Yosemite is not the end of the line for any of them! (Or for earlier Mac minis, either … the Mid 2007 one can only be updated as far as Lion.)

A search of MacTracker also suggests that a Mac mini or Mac mini Server with a Core i5 would be from Mid 2011, Late 2012, Late 2014, or 2018. The Late 2014 model seems to be the only Mac mini for which a Core i5 that was clocked at 2.6 GHz was an option. (Some earlier Mac minis had 2.5 GHz Core i5s.)