Do you need to reinstall OS X regularly to keep your Mac running well? No. Are there times when doing so might be a good idea? Possibly. Here’s when.
It’s a truism among Windows users: you should re-install your operating system every year, if not every six months, to keep things running smoothly. This was probably more true of Windows XP than it is of Windows 8, or even 7 – but it’s still something users of Microsoft’s operating system hear, and act on, regularly. (Author’s note: I intended to make it clear that Windows users don’t need to reinstall regularly, only that this is a common myth among Windows users some Mac users might hear and be curious about. I regret not being clear on this point).
Should Mac users do the same thing?
If your Mac is running well, move along – this is mostly irrelevant to you. Many Mac users use the same installation of OS X for years without having any problems (so do many Windows users, for that matter). But if your Mac is running slowly, or crashing constantly, a fresh installation of OS X might be a good idea.
Why Not Just Reinstall Regularly?
You don’t need to reinstall OS X regularly for maintenance reasons – OS X, if treated well, takes pretty good care of itself. For most people, reinstalling means a lot of work with little payoff.
Reinstalling OS X takes time. You’ll want to backup all of your documents, music and more, and ensure you’ve got a way to reinstall all of the software you’ve collected over the years. You could simply reinstall and restore from Time Machine, but doing so might restore the problems you’re reinstalling to fix.
Knowing all this, are there any times that a reinstallation is a good idea? Here’s a few we could think of.
Everything Is Just… Broken
This is really the main reason you’re going to want to reinstall OS X: when your Mac simply isn’t working right. You see error messages constantly, software won’t run and your computer is generally unusable. Maybe it won’t even boot.
It’s probably more likely to happen if you’re the sort of person who loves constantly installing new software and playing with hidden settings, but even regular users will occasionally end up with an OS X installation so borked that reinstallation is the best path forward.
There are some steps you can take before committing to a reinstallation. I think Yasu is a great first step if your Mac’s not running well, personally – running it and seeing if that solves your problem could save you a lot of time.
If that doesn’t do the trick, you should also try out Onyx, which in addition to giving you access to hidden Mac settings offers all kinds of tools for cleaning up and repairing your Mac. If things are buggy, try this.
But if your Mac crashes often enough to be unusable, and none of this seems to help, a clean installation is a good idea.
When Your Mac Is Slow
Even if your Mac isn’t crashing, you might want to reinstall OS X simply to speed things up. My colleague James offered a bunch of ways to speed up your Mac, and reinstalling OS X completely was one of the steps mentioned.
“A reinstall will speed things by clearing out all the old crap,” James told me. “Preferences, caches from programs that don’t play nicely.”
It’s a good point, but I’d recommend trying Yasu and Onyx to clean these things out before a full reinstallation. I’d also recommend trying out some of his other tips first, but if none of that works a reinstallation might help.
You’re Selling Or Giving Away Your Mac
It’s no secret that Apple hardware holds value – you can probably sell your Mac five years later for a big chunk of the original value, something unheard of when it comes to Windows PCs.
But if you’re giving your Mac to someone else, you don’t want them to have access to your files. This is why you should securely wipe your Mac’s hard drive or solid state drive (there’s an important difference between the two) and reinstall Mac OS X. Doing this means the next owner will have a Mac that runs like new, and that your files will be protected.
You Want To Downgrade OS X
Whether you’ve installed the Yosemite public beta or simply don’t like changes in recent versions of OS X, you might wish you could install an earlier version of Apple’s operating system. After all: on older Macs, newer operating systems may run poorly.
And if you want to do that, your only option is a fresh installation of OS X – Apple does not offer any official tools for downgrading in place (outside of a recommendation that you use a Time Machine backup).
Why Else Might You Reinstall OS X?
These are the main reasons we could think of for reinstalling OS X, but we want to know what you think. Are there any good reasons for starting over that we’re missing here? Let’s talk in the comments below, okay?