Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Mr. RPG

macrumors 6502a
Original poster
Sep 21, 2012
566
0
I just downloaded the Public Beta but how do I do a clean install of the OS? i've never had to reinstall OS X or anything before.
 

tywebb13

macrumors 68040
Apr 21, 2012
3,074
1,738
Do a time machine backup first. Then make a bootable usb installer using instructions in this thread: https://forums.macrumors.com/threads/1757723/

Start up your computer with holding down the option key and boot up from the installer.

Then use the disk utility in the usb installer to erase the drive and then install Yosemite from the usb onto the newly erased drive.

Alternatively, you could make a separate partition and install to that instead.
 

Mr. RPG

macrumors 6502a
Original poster
Sep 21, 2012
566
0
I don't have a USB with enough storage I'm afraid..

Is there no way to simply re-install from the Public Beta without using a USB boot?
 

SanFran95

macrumors member
Jul 18, 2014
41
0
I don't have a USB with enough storage I'm afraid..

Is there no way to simply re-install from the Public Beta without using a USB boot?

Don't know if this also works with OS X Yosemite, but maybe: http://support.apple.com/kb/HT5943
- But wouldn't make a clean install with a Beta unless I had a good backup - it'll be more stable/'safe' to do it when the final version is released ;)
 

thisoldnerd

macrumors newbie
Jul 24, 2014
1
0
I get this error about a second after entering my password. I have used a lacie (8GB) and sandisk (32GB) thumbdrive formated, MACosEJ

open terminal and copy and pasted the string and then nothing.

Password:
Erasing Disk: 0%... 10%...
Error erasing disk error number (-69888, 0)
A error occurred erasing the disk.
iMac:~ user$



can someone please advise?
 

vitaligent

macrumors newbie
Dec 25, 2013
2
0
I get this error about a second after entering my password. I have used a lacie (8GB) and sandisk (32GB) thumbdrive formated, MACosEJ

open terminal and copy and pasted the string and then nothing.

Password:
Erasing Disk: 0%... 10%...
Error erasing disk error number (-69888, 0)
A error occurred erasing the disk.
iMac:~ user$



can someone please advise?

I had this exact error. For me, it was because I had specified the wrong partition name in the command line:

"createinstallmedia --volume /Volumes/Untitled"

You need to check in your /Volumes folder to make sure you're providing a valid path to your blank USB drive.

Hope that helps.
 

merlino165

macrumors newbie
Jun 14, 2014
11
0
Trieste - Italy
Does anyone know if you can do this with the Yosemite Public Beta?


of course no ! mentioned procedure only reinstall existing Operative System

if Recovery Partition owns to Mavericks, it will download and reinstall Mavericks

for a clean install you have to use any USB drive !
 

smokesletsgo

macrumors regular
Oct 23, 2013
166
140
You don't need no USB installers. CMD + R, format the drive and install/download Yosemite from there. Installs perfectly just like any other OS X, tried it.
 

merlino165

macrumors newbie
Jun 14, 2014
11
0
Trieste - Italy
You don't need no USB installers. CMD + R, format the drive and install/download Yosemite from there. Installs perfectly just like any other OS X, tried it.

only if you have already installed Yosemite before and Recovery Partition owns to it
if he needs to perform a clean install from Mavericks has to use a USB installs
 

merlino165

macrumors newbie
Jun 14, 2014
11
0
Trieste - Italy
Agh, which one of you is correct?


if you have already installed Yosemite, and need to perform a clean reinstall, the suggested procedure is correct

if it's the first Yosemite install, there is no way to use a Recovery Partition related to a previous System, to download a new one

You need a USB drive, to prepare a bootable Installer !
 

DeltaMac

macrumors G5
Jul 30, 2003
13,749
4,572
Delaware
Agh, which one of you is correct?

Both are correct - which method to use, is your choice.

You can erase the hard drive OS X partition while booted to the Recovery partition, which you already have. (That's restarting with Command+R)

Or, you can boot to an installer, on a USB device, for example, and erase/install from that installer. That will require a little preparation, as you need to have the installer downloaded, then create the installer on a USB flash drive, or some other drive that you might already have. It might even be a good excuse to spend less than $10, and get an 8GB USB flash drive, that you can dedicate to this purpose…
Erase & Install from your created USB partition/drive will be quicker, as you don't have to wait for the system files to download through your internet connection, so I prefer the bootable installer, too...
 

Mr. RPG

macrumors 6502a
Original poster
Sep 21, 2012
566
0
Both are correct - which method to use, is your choice.

You can erase the hard drive OS X partition while booted to the Recovery partition, which you already have. (That's restarting with Command+R)

Or, you can boot to an installer, on a USB device, for example, and erase/install from that installer. That will require a little preparation, as you need to have the installer downloaded, then create the installer on a USB flash drive, or some other drive that you might already have. It might even be a good excuse to spend less than $10, and get an 8GB USB flash drive, that you can dedicate to this purpose…
Erase & Install from your created USB partition/drive will be quicker, as you don't have to wait for the system files to download through your internet connection, so I prefer the bootable installer, too...

I haven't installed Yosemite before though, so is method 1 still usable? I've only downloaded it.
 

DeltaMac

macrumors G5
Jul 30, 2003
13,749
4,572
Delaware
If you already have the installer - that will work, just launch it.
Your downloaded installer WILL delete itself when it is finished.
If you REALLY want to do a fresh install (that's erase the drive, then reinstall, so nothing from your present drive still is present), then best to make a USB flash drive as a bootable installer.
Again, less than $10 for an 8GB USB flash drive is all you need.
Download the DiskmakerX, which will make the process simple.
http://liondiskmaker.com
You'll notice that DiskmakerX for Yosemite comes in two different versions. One for the Beta, and one for the Developer Preview. Make sure you get the app that matches up with what you downloaded for Yosemite.

Remember that a "Clean Install" means that your present files/pictures/music will all disappear -
After booting to the installer, erase the hard drive using Disk Utility from the installer window. Quit Disk Utility after erasing the hard drive, then continue with the OS X install.
And, there's your fresh install of OS X 10.10...
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
34,463
16,160
California
I haven't installed Yosemite before though, so is method 1 still usable? I've only downloaded it.

If you have never installed Yosemite then you do not have a Yosemite recovery partition, so a command-r boot to recovery is not going to get you Yosemite. You will need to make the USB installer and boot from it then erase the disk and install to get your clean install of Yosemite.
 

Mr. RPG

macrumors 6502a
Original poster
Sep 21, 2012
566
0
If you already have the installer - that will work, just launch it.
Your downloaded installer WILL delete itself when it is finished.
If you REALLY want to do a fresh install (that's erase the drive, then reinstall, so nothing from your present drive still is present), then best to make a USB flash drive as a bootable installer.
Again, less than $10 for an 8GB USB flash drive is all you need.
Download the DiskmakerX, which will make the process simple.
http://liondiskmaker.com
You'll notice that DiskmakerX for Yosemite comes in two different versions. One for the Beta, and one for the Developer Preview. Make sure you get the app that matches up with what you downloaded for Yosemite.

Remember that a "Clean Install" means that your present files/pictures/music will all disappear -
After booting to the installer, erase the hard drive using Disk Utility from the installer window. Quit Disk Utility after erasing the hard drive, then continue with the OS X install.
And, there's your fresh install of OS X 10.10...

I'd really prefer not to do a USB installer though.

Could I just install Yosemite, erase the hard drive, then use recovery to re-install Yosemite?

or any other way that doesn't require a USB?
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
34,463
16,160
California
I'd really prefer not to do a USB installer though.

Could I just install Yosemite, erase the hard drive, then use recovery to re-install Yosemite?

or any other way that doesn't require a USB?

Sure that will work. Just a double download of the data as long as that does not bother you.
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
34,463
16,160
California
I just downloaded the Public Beta but how do I do a clean install of the OS? i've never had to reinstall OS X or anything before.

Why would I need to download anything..?

Well you already downloaded the installer, so you can just run that now and install over top of Mavericks and that will create a Yosemite recovery partition that can be used to install Yosemite.

So then you will command-r boot to recovery and you will then be running from the Yosemite version of the recovery partition. Then you erase Macintosh HD and click reinstall OS. When you do that it will redownload Yosemite and install it. It is this second DL of the OS I was referring to.

When you boot to recovery to reinstall there is no way to reuse the installer you already downloaded, you will need to let the recovery system download another opt to be installed.

Disclaimer: This is how it works in recovery on prior OS versions, and from what I have read here Yosemite works the same way, but I have not tested this myself with Yosemite.
 

DeltaMac

macrumors G5
Jul 30, 2003
13,749
4,572
Delaware
The installer files are not kept on your computer, except for the initial installer app.
If you install Yosemite, just to erase, then reinstall yosemite - your initial installer app is gone (deletes itself after the install), and all the system files get downloaded again.
You can copy your downloaded Yosemite installer app to another drive, so you'll still have that copy (meaning you'll need some kind of external storage anyway :D )
Try to rethink about the USB installer. The process will keep the installer local, so you can reinstall, even without an internet connection. The DiskmakerX app is very simple to use, and then you have your installer whenever you might need to use it (along with an independent location for a few simple utilities that you might like to have, particularly if your hard drive has to be replaced.
And, an 8GB thumb drive is less than $10. I must have 20 of those (good bargain a few months ago :D ($4 each, got 5 then)
 

Mr. RPG

macrumors 6502a
Original poster
Sep 21, 2012
566
0
Alright guys I'll just do the bootable USB installer. Thanks for the information!
 

537635

macrumors 65816
Mar 7, 2009
1,152
1,040
Slovenia, EU
I read in another topic, that beta version of Yosemite does not upgrade the recovery partition.

Can somebody please confirm whether it does or doesn't? I would rather just upgrade and then do the fresh install via cmd+r.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.