Hello, I am looking for instructions on how to clean install Yosemite as the reviews on the apple store all say there are problems simply downloading the upgrade. I have 10.8.5 and need to know how to reformat disk and do a clean install. I have a time machine.
Thanks,
iMac (21.5-inch Mid 2011), OS X Mountain Lion (10.8.5)
I had no problems with the Upgrade. People who have problems with just upgrading usually have system modifications installed that don't work with Yosemite.
If you install anything with an installer, you need to check for updates prior to upgrading your OS. If there aren't any updates available, you need to be prepared to uninstall that system mod if you run into problems.
Depending on how much junk you install on your Mac, erasing and installing might just be the best solution over updating the system mods.
To erase and install, you will need to boot into Recovery and erase the hard drive using Disk Utility. Then, Quit DU and reinstall the OS.
That will install Mavericks (10.8.5).
Note that things like iPhoto, iMovie, etc. are not part of the OS. You will need to either re-download them from the App Store or install from the DVDs that came with your Mac.
When the Setup Assistant runs during first boot, choose to Migrate from your Time Machine backup. https://support.apple.com/en-us/HT204350
If people are having trouble downloading the update, then that's completely unrelated to doing a clean install, which is what you might do once you've successfully downloaded it!
A clean install is only necessary if you have got your system into a complete mess, and you want to start from a clean slate. If you're going to restore all your apps, user settings, etc, back afterwards, then the more of that you do, the less beneficial the whole exercise is.
In 13 years, I've done about 2 clean installs. Otherwise, I've upgraded every OS version over the top of an existing install, and migrated everything across 5 Macs.😁
clean install yosemite
