Arei
Level 1 (4 points)
Desktops

Q: Should I be able to do a clean install of El Capitan *without* wiping out my Windows partition?

I bought this Mid 2011 27" iMac used earlier this year as a refurb from a reseller. It came with El Capitan installed, but I have a hunch they did an upgrade installation versus a clean install. The computer suffers from slow booting and slow program loading (but once it loads then its just fine). The same thing happened with my old iMac when I did an upgrade from Leopard to Snow Leopard years ago, and erasing the drive and performing a clean install of OSX (and putting files and programs back with Time Machine) solved those problems then. So I figured it wouldn't hurt to try a clean install on this machine.

 

But reading tutorials I've noticed that if you're not the original owner of the computer, then you can't install OSX updates without resetting the entire computer? Though I HAVE been able to install OS updates through the App Store (and I thought I binded my Apple ID to the machine when I initially set it up), doesn't that mean I should be able to perform the clean install, or is it going to have to be entirely reset?

 

Yes I have run disk utility and checked my HHD drive, it's functioning fine. The whole computer is nice and quiet, not making any abnormal sounds or performing unusually, its just really the slow boot into OSX and slow loading programs that are the problem.

 

Also I just recently created a Windows partition and installed Windows 8.1. It boots and runs decently faster than OSX, so I'm thinking its just a problem with OSX and not the HHD itself and doing a clean install will hopefully solve the issues. This computer gave me a lot of grief creating a partition to install Windows 8.1 (unlike my old iMac) so I really really really would not like to have to wipe the entire HHD to "change ownership" and have to mess with that again...

 

It "sounds" like since the app store IS letting me install OS and program updates with my Apple ID, that I SHOULD be able to boot into the RecoveryHD Partition and from there do a fresh install of OSX over *just* my existing Mac partition. And this shouldn't erase my *entire* HHD, just the Mac partition. I'm going to back up my entire Windows partition just to be safe, though. I haven't been able to find a guide that specifically deals with only resetting the OSX partition and not wiping out Windows in the process, so I wanna make sure I have my facts straight. I planned on resetting OSX then restoring my files with Time Machine. Though I also want to make sure that it's going to allow me to even get in there and reset the OS in the first place since I'm not the original owner of the iMac and I don't know if they reset it properly.

 

Sorry for the extremely long question, and TIA!

iMac, OS X El Capitan (10.11.6)

Posted on Sep 6, 2016 6:11 PM

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Q: Should I be able to do a clean install of El Capitan *without* wiping out my Windows partition?

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  • Helpful answers

  • by RIFerrarr,Helpful

    RIFerrarr RIFerrarr Sep 6, 2016 11:09 PM in response to Arei
    Level 3 (689 points)
    Mac OS X
    Sep 6, 2016 11:09 PM in response to Arei

    Open the Mac App Store, make sure you are logged in with your Apple ID and click on the Purchased tab. Look to see if El Capitan is associated with your Apple ID. If it is not, you will need to download it so it will be associated with your Apple ID. If it is, you are all set.

     

    Updates are to the OS X, not the purchaser, so you can install all the updates, but the OS needs to be associated with your Apple ID.

     

    I am not sure about the Windows issue, how did you install Windows? With Boot Camp? You may be able to clone it to another drive (if you have one) using Clonezilla. Then wipe and reinstall El Capitan, and set up Boot Camp partition and clone back.

  • by John Galt,Helpful

    John Galt John Galt Sep 6, 2016 11:09 PM in response to Arei
    Level 8 (48,346 points)
    Mac OS X
    Sep 6, 2016 11:09 PM in response to Arei

    The short answer to your long question is yes: you can completely erase the OS X partition, and subsequently reinstall OS X on that volume. Just don't alter the existing partition map.

     

    There is one slight caveat. Apple stopped shipping Macs with discs in approximately August 2011. The model designation did not change. If yours was built before then, the reseller should have included its original System Install DVD which contains Snow Leopard. If you do not have that disc, you will require a retail Snow Leopard DVD to reinstall its originally installed operating system, and subsequently upgrade to El Capitan.

     

    To resolve that unknown, boot OS X Internet Recovery (read the note). It will offer to reinstall Lion, which will not require an Apple ID to install. Booting OS X Recovery from the Recovery Partition will enable you reinstall the version it previously contained. Assuming you purchased El Capitan, it will ask for your Apple ID to reinstall it on that Mac.