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tywebb13

macrumors 68040
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Apr 21, 2012
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Now that El Capitan PB1 is released if you want to make a bootable usb, format an 8 GB or preferably a 16 GB USB3 drive* which should be called Untitled and formatted as Mac OS Extended (Journaled). The installer should be called Install OS X El Capitan Public Beta.app and should be in your Applications folder.

Run this in terminal and wait about 20 minutes:

sudo /Applications/Install\ OS\ X\ El\ Capitan\ Public\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan\ Public\ Beta.app --nointeraction

You can boot up from it by selecting it from the startup manager you get when starting your computer and holding down the option key.

If the installation creates a core storage logical volume you can revert it to get partitions back to normal by running these 2 commands in terminal.

diskutil cs list

and then

diskutil coreStorage revert lvUUID

where lvUUID is the last lvUUID reported by the previous Terminal command.

Then restart for everything to get back to normal after you have run these commands in Terminal.
----------------------------------------------------------------
* - note if your usb is too slow or too small you may get an error "Mount of outer dmg failed" because it did not copy over the invisible files that make the usb bootable. So it is better to use a 16GB USB3 rather than a 8GB or USB2.
 
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csilvertooth

macrumors newbie
Sep 26, 2012
6
1
Now that El Capitan PB1 is released if you want to be able to make a bootable usb, format an 8 GB USB drive which should be called Untitled and formatted as Mac OS Extended (Journaled). The installer should be called Install OS X El Capitan Public Beta.app and should be in your Applications folder.

Run this in terminal and wait about 20 minutes:

sudo /Applications/Install\ OS\ X\ El\ Capitan\ Pubic\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan\ Public\ Beta.app --nointeraction

You can boot up from it by selecting it from the startup manager you get when starting your computer and holding down the option key.

If the installation creates a core storage logical volume you can revert it to get partitions back to normal by running these 2 commands in terminal.

diskutil cs list

and then

diskutil coreStorage revert lvUUID

where lvUUID is the last lvUUID reported by the previous Terminal command.

Then restart for everything to get back to normal after you have run these commands in Terminal.


I made an applescript a while back to make things a bit easier. I just tested with El Capitan and updated the info. If anyone is interested here is the link.

http://musings.silvertooth.us/2015/...tan-os-x-bootable-media-creator-1-25-is-here/

Cheers,

Chris
http://musings.silvertooth.us
 

tywebb13

macrumors 68040
Original poster
Apr 21, 2012
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When you say you tested with El Capitan, do you mean developer preview, public beta or both? The sudo command I used is slightly different to the one for the developer preview because the installer names are different.

So will the script work with PB1 as well as DP1?
 

csilvertooth

macrumors newbie
Sep 26, 2012
6
1
When you say you tested with El Capitan, do you mean developer preview, public beta or both? The sudo command I used is slightly different to the one for the developer preview because the installer names are different.

So will the script work with PB1 as well as DP1?

I have only tested with the public beta. My dev subscription expired so I don't have access to the DP release but I would imagine they work fine.
 

Apple_Robert

Contributor
Sep 21, 2012
35,647
52,437
In a van down by the river
Now that El Capitan PB1 is released if you want to be able to make a bootable usb, format an 8 GB USB drive which should be called Untitled and formatted as Mac OS Extended (Journaled). The installer should be called Install OS X El Capitan Public Beta.app and should be in your Applications folder.

Run this in terminal and wait about 20 minutes:

sudo /Applications/Install\ OS\ X\ El\ Capitan\ Pubic\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ Capitan\ Public\ Beta.app --nointeraction

You can boot up from it by selecting it from the startup manager you get when starting your computer and holding down the option key.

If the installation creates a core storage logical volume you can revert it to get partitions back to normal by running these 2 commands in terminal.

diskutil cs list

and then

diskutil coreStorage revert lvUUID

where lvUUID is the last lvUUID reported by the previous Terminal command.

Then restart for everything to get back to normal after you have run these commands in Terminal.
I get a "command not found" error in terminal when doing a copy and paste.
 

tywebb13

macrumors 68040
Original poster
Apr 21, 2012
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Also the installers are getting bigger thesedays, so I think a 16GB USB3 will be faster than a 8GB USB2.

Up until Yosemite I've been using 8GB USB2s but they are pretty slow.

Now with El Capitan it's pretty big. Bigger than Yosemite. So for El Capitan I use 16GB USB3.
 

chekz0414

macrumors 6502a
Jul 3, 2011
770
99
FL
I'm trying it on an 8GB as we speak. I need to fresh install since I think my Finder is buggy. I can use Migration Assistant on a Time Machine Backup right? For my Documents, and iTunes Library right?
 

tywebb13

macrumors 68040
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Apr 21, 2012
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It probably will still fit onto an 8 GB one. But there won't be much room left on it. There is other stuff copied over, not just the installer app. There are some invisible files too which makes the thing bootable, but they take up more space. That's why I prefer the 16 GB nowadays.

And how much bigger are they going to get? By 10.11.5 it might not even fit onto an 8GB anymore.

Is it a USB2 or USB3? The USB3 will be faster.

I haven't use migration assistant with el capitan so I don't know if that will work.
 
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crjackson2134

macrumors 601
Mar 6, 2013
4,847
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Charlotte, NC
I haven't installed the PB onto a USB stick yet, but the DB installed perfectly onto an 8GB stick using DiskMaker X. It did however incorrectly label it Yosemite, but it was fine otherwis. I'll try it in a few days with the PB1. I was using the 4b4 version.

Sometimes however, I just launch the installer from within my working version and point it to my target drive. Is there a downside to doing it this way? It way faster.
 
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tywebb13

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Apr 21, 2012
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There is a lot more to a bootable usb than the installer.

You can use it to format the whole drive if necessary.

Or run terminal commands from outside your main drive.

Or something I have done several times is use it, not to actually install the system but rather facilitate a time machine full restore.

So yeah you can just run the installer app itself if you want but just beware that if you do this just after it downloads it deletes itself. So if you just want to run the app, be sure to make a copy of it first somewhere.

Also, if you want to do a clean install, the bootable usb is probably better.
 
Last edited:

crjackson2134

macrumors 601
Mar 6, 2013
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Charlotte, NC
There is a lot more to a bootable usb than the installer.

You can use it to format the whole drive if necessary.

Or run terminal commands from outside your main drive.

Or something I have done several times is use it, not to actually install the system but rather facilitate a time machine full restore.

So yeah you can just run the installer app itself but just beware that if you do this just after it downloads it deletes itself. So if you just want to run the app, be sure to make a copy of it first somewhere.

Also, if you want to do a clean install, the bootable usb is probably better.

Oh yeah, I know that. I always copy to a different drive beforehand. I use my USB for the same reasons, I just wanted to know if there was something else I didn't consider. That said, I usually prep. the drive with DU running the previous OS version and launch the installer from SSD and install to SSD. It's a really quick install that way. Clean install of the released version is a different matter.
 

tywebb13

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Apr 21, 2012
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It might sound like overkill but I always also do a time machine backup just before and just after each beta update. Why go to so much trouble? Because I know I have literally all beta versions backed up onto my external hard drive. So if ever I have to downgrade, I can do so to any previous version via time machine.

Anyway apple recommend you backup before installing betas (and I would go further than apple and say to do it before any system update - beta or not).
 

crjackson2134

macrumors 601
Mar 6, 2013
4,847
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Charlotte, NC
It might sound like overkill but I always also do a time machine backup just before and just after each beta update. Why go to so much trouble? Because I know I have literally all beta versions backed up onto my external hard drive. So if ever I have to downgrade, I can do so to any previous version via time machine.

Anyway apple recommend you backup before installing betas (and I would go further than apple and say to do it before any system update - beta or not).

Yup, I do that too. Not an overkill at all. I actually do a TM backup on 2 different drives (1 spinner and 1 SSD).
 

tywebb13

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Apr 21, 2012
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And data is more valuable than systems or hardware which can be replaced. Most of my data can't be replaced. So I do a 5-way backup of data - I use cloud storage, 2 hard drives (1 on site and 1 off site) and burn everything to 2 lots of blu rays (again 1 lot kept on site and the other lot off site).

Is that overkill? Probably is for systems, but I would argue not for data.
 

crjackson2134

macrumors 601
Mar 6, 2013
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Charlotte, NC
Ha ha
And data is more valuable than systems or hardware which can be replaced. Most of my data can't be replaced. So I do a 5-way backup of data - I use cloud storage, 2 hard drives (1 on site and 1 off site) and burn everything to 2 lots of blu rays (again 1 lot kept on site and the other lot off site).

Is that overkill? Probably is for systems, but I would argue not for data.

Ha Ha Ha... I use 2 TM drives, 2 uncompressed copies on 2 other spinners, and BD's also. I once lost 15 years worth of data on a catastrophic hardware failure. Well, not really lost, but close. I recovered most of it from CD and DVD backups. I have since started using BD too. The "outdated" optical media saved my bacon. I never forgot that and still have those old backups. They're all still good too.
 

tywebb13

macrumors 68040
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Apr 21, 2012
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In case the automated processes createinstallmedia, os x bootable media creator or diskmakerx don't work you can do it all manually yourself.

Just format your usb as Mac OS Extended (Journaled) named Untitled and then run the following 5 commands in terminal:

sudo hdiutil attach /Applications/Install\ OS\ X\ El\ Capitan\ Public\ Beta.app/Contents/SharedSupport/InstallESD.dmg

sudo asr restore -source /Volumes/OS\ X\ Install\ ESD/BaseSystem.dmg -target /Volumes/Untitled -erase -format HFS+

sudo rm /Volumes/OS\ X\ Base\ System/System/Installation/Packages

sudo cp -a /Volumes/OS\ X\ Install\ ESD/Packages /Volumes/OS\ X\ Base\ System/System/Installation/Packages

sudo cp -a /Volumes/OS\ X\ Install\ ESD/BaseSystem.dmg /Volumes/OS\ X\ Install\ ESD/BaseSystem.chunklist /Volumes/OS\ X\ Base\ System
 
Last edited:

tywebb13

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Apr 21, 2012
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Or if usbs aren't quite your thing you could make a bootable dvd instead (and if el capitan gets too big for that later, I'll update these instructions on how to make a bootable blu-ray of el capitan).

To make a bootable DVD of El Capitan:

After downloading the full El Capitan Public Beta installer app from the Mac App Store, run these 14 commands in Terminal to create an elcapitan.iso file and then burn it to a dual layer DVD with Disk Utility or some other disk burning utility. You may then boot up from it by holding the option key down and then install El Capitan.

hdiutil attach /Applications/Install\ OS\ X\ El\ Capitan\ Public\ Beta.app/Contents/SharedSupport/InstallESD.dmg -noverify -nobrowse -mountpoint /Volumes/install_app

hdiutil convert /Volumes/install_app/BaseSystem.dmg -format UDSP -o /tmp/elcapitan

hdiutil resize -size 8g /tmp/elcapitan.sparseimage

hdiutil attach /tmp/elcapitan.sparseimage -noverify -nobrowse -mountpoint /Volumes/install_build

rm /Volumes/install_build/System/Installation/Packages

cp -rp /Volumes/install_app/Packages /Volumes/install_build/System/Installation/

cp -rp /Volumes/install_app/BaseSystem.chunklist /Volumes/install_build

cp -rp /Volumes/install_app/BaseSystem.dmg /Volumes/install_build

hdiutil detach /Volumes/install_app

hdiutil detach /Volumes/install_build

hdiutil resize -size `hdiutil resize -limits /tmp/elcapitan.sparseimage | tail -n 1 | awk '{ print $1 }'`b /tmp/elcapitan.sparseimage

hdiutil convert /tmp/elcapitan.sparseimage -format UDTO -o /tmp/elcapitan

rm /tmp/elcapitan.sparseimage

mv /tmp/elcapitan.cdr ~/Desktop/elcapitan.iso
 
Last edited:

krendel

macrumors newbie
Jun 23, 2015
13
4
Erasing Disk: 0%... 10%... 20%... 30%...100%...
Copying installer files to disk...
Copy complete.
Making disk bootable...
Mount of outer dmg failed.
Done.


Got this error after trying to write PB1 on 8gb usb. Reinserted flash manually - it shows its content fine. Gonna try to install pb1 on separate partition, but maybe someone is aware of the reason of this error?
 

tywebb13

macrumors 68040
Original poster
Apr 21, 2012
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"Mount of outer dmg failed."

Yeah well that is why I said to use a USB3 and preferably a 16GB one.

There are 2 theories about this error.

1 - the download itself is corrupt and you need to redownload.

2 - the USB couldn't handle the transfer and you need to use a better usb.

Both are valid concerns, but in this instance I'd say the more likely culprit is the second theory.

You might be able to see the visible files but the ones that make it bootable are invisible and did not copy over properly. So you won't be able to boot from it.

You could either try a better usb or alternatively use my manual method in post #19 at https://forums.macrumors.com/threads/el-capitan-pb1-bootable-usb.1899261/#post-21573292
 

Apple_Robert

Contributor
Sep 21, 2012
35,647
52,437
In a van down by the river
Erasing Disk: 0%... 10%... 20%... 30%...100%...
Copying installer files to disk...
Copy complete.
Making disk bootable...
Mount of outer dmg failed.
Done.


Got this error after trying to write PB1 on 8gb usb. Reinserted flash manually - it shows its content fine. Gonna try to install pb1 on separate partition, but maybe someone is aware of the reason of this error?
I got that error three times last night. I chose a different USB (2.0) stick and it worked like it should.
 

krendel

macrumors newbie
Jun 23, 2015
13
4
Thanks for replies. Simple moving Install OS X El Capitan Public Beta.app to home directory and writing it to the same flash drive with these commands worked like a charm. Install to separate partition also went fine, very smooth one so far :)
 

tywebb13

macrumors 68040
Original poster
Apr 21, 2012
3,079
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It seems that this error "Mount of outer dmg failed" is much more common with PB1 than with DP1. So it could be a bug with PB1.
 
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