Install and run OSX 10.10 on external USB hard drive

[tricky99]

So I'm struggling to work out if this is possible.

I've run the installer, selected the external drive during initial drive selection and my macbook then booted from the external drive. But, when I'm asked where to install OSX 10.10 the only option is the internal Macintosh HD drive.

Could this because I forgot to check if the external drive had ownership enabled?

Or would I need two external drives connected so I can install from one to the other?

Any help appreciated..

 

[AndyK]

Formatted to a GUID partition scheme and Mac OS Extended (Journaled) as the format type?

 

[tricky99]

Thanks for the reply Andy - yes I formatted the drive in order for it to show up as an option in the installer.

Have others managed to do this successfully?

 

[maflynn]

Did you try using the USB installer method? That is create a Yosemite bootable USB thumb drive?

 

[tricky99]

Did you try using the USB installer method? That is create a Yosemite bootable USB thumb drive?

Not yet as I've only got an 8GB USB drive at the minute.

So if I had a 16 or 32 GB USB could I run the installer off the USB and then install and run 10.10 off the external hard drive?

Is the issue that I can't run the installer off the same drive that I want to install on?

 

[AndyK]

Is the issue that I can't run the installer off the same drive that I want to install on?

This will cause you issues yes. Run it from a separate place.

 

[bennibeef]

I did this: Loaded Yosemite -> open installer -> select my usb SSD/HDD -> continue-> restartet and yosemite got installed on the usb drive - no problems at all except starting the mavericks partition again without the drive was a bit of a hassle because it did not find my old partition and always wanted to start from the yosemite installer but there was a option in Apple Menu to boot another partition (where I was able to select Mavericks) since then it works flawlessly

 

[AndyK]

I did this: Loaded Yosemite -> open installer -> select my usb SSD/HDD -> continue-> restartet and yosemite got installed on the usb drive - no problems at all except starting the mavericks partition again without the drive was a bit of a hassle because it did not find my old partition and always wanted to start from the yosemite installer but there was a option in Apple Menu to boot another partition (where I was able to select Mavericks) since then it works flawlessly

You can also just hold the option key as you boot & you'll be presented with all boot choices.

 

[bennibeef]

You can also just hold the option key as you boot & you'll be presented with all boot choices.

Well the long story of this was that: I shut down Yosemite with the USB SSD plugged in, started with option key down - there was no Mavericks

shut down unplugged started - yosemite installer started

shut down started with option down again no Mavericks

shut down started - started yosemite installer again - went to Apple Menu in the installer boot another partition there was my Mavericks SSD - booted it - now everything works again.

 

[AndyK]

Weird, I've done my install on a partition of my rmbp sad, so haven't tried it on a usb.

If you keep having issues it's worth a try if you have ~ 30gb+ for testing handing around.

 

[tricky99]

I did this: Loaded Yosemite -> open installer -> select my usb SSD/HDD -> continue-> restartet and yosemite got installed on the usb drive - no problems at all except starting the mavericks partition again without the drive was a bit of a hassle because it did not find my old partition and always wanted to start from the yosemite installer but there was a option in Apple Menu to boot another partition (where I was able to select Mavericks) since then it works flawlessly

What you did is what I planned to do and I expected it to work so unless it was something to do with the USB hard drive not having being granted ownership I think it might be down to the connection of the Western Digital drive I'm using being a bit flaky on the USB 3.0 of my late 2013 rMBP.