Clean Install without formatting?

[lixe]

Hi,

I don't know what it is exactly but my Mac is keeping panic errors like every half an hour since today... I wanted to try the new "Duet Display" App, maybe installing it caused this... the strange thing is Disk Utility can fix permission errors but not permanent... even reinstalling Yosemite again didn't change anything...

However my idea is now to get a clean install, because it can't be a bad idea anyhow but instead of backing everything up (which I also do) and formatting the disk I started to think if it wouldn't be also possible to move everything on my disk to a folder, then install Yosemite and move the files I need... everything else I can delete then... what do you guys think? I don't see a problem why it shouldn't work and it saves me a lot of time, because I would have to copy 1TB of photos back onto my mac after formatting

Thanks!
Felix

 

[Weaselboy]

That would not be the same thing. For a true clean install you need to erase the entire disk, then reinstall the OS then manually reinstall all your apps and data.

You could move your data folder like Documents and Pictures for example to an external drive and do a clean install, then copy them back though.

 

[ncrypt]

I wanted to do something similar and ended up doing the following:

1) Installing Yosemite to a partition on a USB drive and on another partition setting up a bootable Yosemite installer
2) Booting from the USB Yosemite installation and deleting all folders on my Mac hard drive apart from the users folder (effectively wiping the old system off)
3) Renaming the 'users' folder to 'Users-old'
4) Booting from the Yosemite installer partition and installing Yosemite to my internal drive
5) Once everything had installed, I just copied stuff from the Users-old folder into my new user folder

Will be interested to hear how you decide to go about it!

 

[grahamperrin]

… For a true clean install you need to erase the entire disk,

If there's more than one volume, it should suffice to erase the volume to which the OS will be installed.

then reinstall the OS

That will be clean.

then manually reinstall all your apps and data. …

That will be no longer clean.