If you're running an older version of OS X (e.g., Mavericks or Mountain Lion) and the tech department is telling you to use Managed Software Center to upgrade to Yosemite, this is how you do it.
- Set aside time for this upgrade. Keep in mind the entire process can take between 45-90 minutes. You will not be able to use your Mac for other things while this upgrade is happening.
- Back up important files. In theory, the upgrade shouldn't affect your data but make sure your CrashPlan has been running and completing backups before you start this upgrade process.
- Plug your computer in. If you have a laptop, even though your laptop battery will likely last longer than even two or three hours, you don't want to risk your battery running out before the upgrade process is complete.
- Do the upgrade at school. The network bandwidth at school is better than what you have at home, so the download of the update won't take as long as school, and the Managed Software Center will not work when you are at home. More importantly, Yosemite is no longer available in the Mac App Store.
- Don't be afraid to ask for help. The upgrade process, as outlined below, is fairly straightforward, but if you're at all nervous about it, feel free to drop by the tech office, and we'll be more than happy to walk you through it.
Click the Install button underneath it.
Click the Updates tab to check on the progress of the download. The download is several gigabytes in size (i.e., quite large), so the download may take a while (even with the school's Internet connection).
Then, click Log out and update.
At this point in the process, it'd be a great time to eat lunch, go for a walk, meet with a student, or engage in any activity that doesn't involve needing your Mac.
Just let it all run. A few more screens may flash by quickly. You won't need to do anything again until you get to a login screen. As always, if you get stuck or have questions, ask the folks in the tech office. We're more than happy to help.
Even though El Capitan is now the official latest release, not Yosemite, the same principle should apply. If you're using Munki, you can use createOSXinstallPkg to make a Munki-able package from an Install OS X Yosemite.app package.
Once you have the Install OS X Yosemite.app downloaded to your /Applications folder and you have the createOSXinstallPkg-master.zip downloaded and extracted to your ~/Downloads folder, just run these commands:
sudo ./createOSXinstallPkg --source /Applications/Install\ OS\ X\ Yosemite.app