Yosemite is only available for people who had downloaded it previously, otherwise it is no longer available.
All University Mac users are strongly advised to upgrade from OS X Yosemite operating system to macOS Sierra (v10.12.6), as soon as possible, as Yosemite is no longer supported by Apple. The upgrade will help to ensure that Macs have the latest security, features, and remain compatible with other University systems. Step 2: Install Mac OS X Yosemite. Now it’s time to actually install OS X. There are a few ways to do this, but we recommend UniBeast for those new to the process, and Clover for more advanced.
You could probably upgrade to macOS Sierra if your Mac qualifies, otherwise you will be able to update to
Mac OS X El Capitan from here, Upgrade to OS X El Capitan - Apple Support
![Mac Mac](/uploads/1/2/6/6/126613114/910602443.jpg)
As both of these operating systems are a few upgrades newer than Mountain Lion you will need to prepare yourself.
Make sure you have enough RAM, 4GBs is minimum. Make sure third party apps you use now are supported under El Capitan or Sierra and have updates available, https://roaringapps.com/apps?platform=osx. Also make sure that any peripherals such as printers, scanners etc are supported under El Capitan and Sierra check with the manufacturers of these items for updated drivers / software etc.
What Uad Driver Do I Need For Mac Os Yosemite To High Sierra
iPhoto and Aperture if you had it are no longer supported by Apple in favour of their new Photos app.