How to clean install OS X while keeping my files?

[497902]

How can I do a clean install of OS X over my current system while keeping my files? In the end I want to have a clean install of OS X just like it is on a brand new Mac - with the exception that my files are still there.

No, my external SSD isn't big enough for a full back up and I just don't want to re-download all my iTunes media.

 

[maflynn]

The only way to have a clean install, is to back up your data and reformat. The other option is to upgrade which will install the OS, but keep your home folder intact which in sense is what your'e asking.

 

[AndyK]

Pretty sure you can't if you want it fresh clean, keeping your files would defeat the purpose of that.

If you don't have enough storage for backups, how are you backing up your stuff in case of system failure?

 

[497902]

If you don't have enough storage for backups, how are you backing up your stuff in case of system failure?

Most of that stuff is just iTunes Media, if I lose it I will still be able to re-download it via iCloud. But that takes a very long time and that's why I'm asking. The rest is (of course) on my external SSD.

So do I really have to calculate with an entire day to clean install my system?

 

[AndyK]

It takes 30 mins? to re install os x, then just download stuff while you sleep then pause when awake.

 

[497902]

It takes 30 mins? to re install os x, then just download stuff while you sleep then pause when awake.

Yep, but this doesn't work in practice. When I wake up 1/3 - 1/2 of all downloads have stopped and I can try again.

 

[robgendreau]

A "clean" installation "over" existing stuff isn't really clean, if that's your question.

You can reinstall system software, as someone already answered.

You can backup all your user data, and then reformat your drive, reinstall software, and migrate or manually copy back your user data.

But even that isn't "clean" in the sense of a new Mac. Your preferences, caches and a bunch of other stuff would still be there. So erase everything and start over, like a clean new Mac, or live with the fact that some of the old unclean stuff with still be there.

 

[m4v3r1ck]

I did it my way...

My interpretation of a clean install:

1. OnyX your existing OS X
2. After first boot, back-up your 'cleaned' OS X to external drive with CCC
3. Reformat your OS X HDD/SSD
4. Clean install OS X
5. Migrate from your (OnyX cleaned) back-up

Clean as it can get?

 

[smithrh]

This is absolutely do-able, but there are caveats.

Overall:

• Partiton the boot disk, give yourself a new partition - you won't lose any data
• Do a clean install to the new partition
• Enjoy

OK, that's over-simplication. Doing a clean install to the new partition can involve at least a little work, but I've done it a few times now.

The caveats come in when you realize you have a lot of duplicated apps, and of course you've doubled your disk usage where the OS is concerned, which may or may not be an issue.

You'll also have two /Users directories, two home directories and so on.

There are also apps which will require re-installation, Office was one of them. Oddly enough, somehow, some way Office picked up on the old partition's preferences, and insisted on saving files to the old desktop.

Depending on how many files you have and where they are, you might opt to copy all of them to the new partition and then at some point nuke the old partition.

Again, not technically impossible or even hard, but there are things to watch out for.