Mountain Lion on a USB

Ok, so to get Mountain Lion onto a USB use the same method as on Lion

First of all, you will need the following

1. Install OS X Mountain (4.37GB download from the Mac App Store)

2. 8GB USB Key

Once you have these you will need to get the Mountain Lion Disk Image, which is obtained by clicking on Finder and pressing SHIFT CMD G at the same time and entering

/Applications/Install OS X Mountain Lion/Contents/SharedSupport/

and then clicking the Go button

Once the folder opens then you need to click on the InstallESD.dmg and press CMD C to copy it, then click on your Desktop and press CMD V to paste it

Once it’s copied to your dekstop rename it 10.8.dmg

Double click on the 10.8.dmg to mount it

Next, insert your USB Key and erase it using Disk Utility as follows

1. click on the device in Disk Utility

2. click on the Erase tab in the middle of the main window

3. choose Mac OS Extended (Journaled) from the format dropdown menu

4. name it Mountain

5. then click the Erase button

6. now click on the Restore tab

7. drag the Mac OS X Install ESD volume onto the Source field

8. drag the Mountain volume onto the Destination field and click on the Restore button

you may be prompted for your admin username and password, so enter this, then the task will start and should take around 15-20 minutes (depending on the speed of your USB2 key)

For a video taking you through the installation process once you have created your USB then click on the link below

Mountain Lion – Reformat & Clean Installation

Format an external hard drive to use with Macs & PCs

Now occasionally Mac users are forced to share files with Windows users, and if using an external hard drive you will need to make sure it is readable/writable in both OS’s

To do this, you will need to format the drive as FAT, this can be done with Disk Utility as follows
1. Plug your USB Drive into the Mac
2. Open Disk Utility
3. Click on your hard drive on the left and then click on the Partition tab in the middle window
4. Click on the drop down menu under Partition Layout and choose 1 partition (or more if you wish)
5. On the right hand side choose MS-DOS (FAT) from the Format menu and give it a name
6. Click Options underneath the partition window and choose Master Boot Record and click OK
7. Click Apply, and the partitioning will proceed, once this is done then you will have a FAT formatted hard drive and the ability to use the drive with both Mac & Windows machines

How do you wipe an old MacBook Air?

So, I was asked this the other day, and it can be quite tricky, basically, you need to boot from an installation disk and run Disk Utility to erase the disk.

Now as the MacBook Air doesn’t have FireWire then Target Disk Mode is pretty much out of the question (although this is now an option on Thunderbolt equipped MacBook Airs), so we will have to either try a remote disk option, or boot from USB.

In this guide I will run through the steps required to complete this task using a bootable USB key, but if you wish to go the Remote Disk option then more info can be found on Apples Support Site at

For this you will need

  1. An 8GB USB key or Hard Drive (or larger)
  2. A Retail Operating System Disk
  3. A Mac with a Superdrive

Ok, so first of all if you have any data on the USB key, make a backup of any data you have on your USB key

On your Superdrive equipped Mac, insert your Operating System Disk & USB key and open Disk Utility

In Disk Utility, click on the OS Disk and then click on the ‘New Image’ icon at the top of the window, pick a name and save it to your Desktop

Once the image is created it will appear in the left hand window of Disk Utility, click on it and then click on ‘Images’ in the menu bar at the top of the screen and choose ‘Scan Image for Restore’

Once that has verified your image, click on your USB key in the left hand window and and choose the ‘Restore’ tab in the main window.

Next drag the image you created to the ‘Source’ field and drag the USB key to the ‘Destination’ field, tick the box that says ‘Erase Destination’ and click on ‘Restore’.

This will erase your USB key and replace it with the contents of your image, so all of the files on the OS disk will be transferred to the USB key, with the end result being a bootable USB key

Once this has completed, eject the USB key and plug it in to your MacBook Air and hold down the ALT key whilst powering it on, you should be presented with the option to boot from the hard drive or the USB key, if you have set a firmware password though you will need to enter this to gain access to the boot menu

When you have booted from the USB key it will vary depending on which OS you have created it from, but usually you will have to agree to a license agreement to get to the pre installation screen, at the top of the screen you should see a Utilities menu, you must click on this and run Disk Utility.

When you are in Disk Utility click on the hard drive you wish to erase, then click on the erase tab, you can then choose which type of deletion you require, I would choose the highest security option, which involves multiple passes of the hard drive, but this can take several days depending on hard drive size, if you don’t have the time then choose a lower security option, but remember more secure = many hours = less chance of data being recovered.

Dealing with Directory Corruption

If your Mac is running slow, there is a chance that you could be suffering from Directory Corruption, to find out if you are the you will need to do the following

Open Disk Utility and click on your system volume, then choose Verify Disk

If all is well then it will tell you with the following notification

Verifying volume “Macintosh HD
Checking file systemPerforming live verification.
Checking Journaled HFS Plus volume.
Checking extents overflow file.
Checking catalog file.
Checking multi-linked files.
Checking catalog hierarchy.
Checking extended attributes file.
Checking volume bitmap.
Checking volume information.
The volume Macintosh HD appears to be OK.

If you get any other message, usually in red, then you will need to repair your disk, you can’t normally do this from within the Operating System, so you will need to boot from an external device, or if you are running lion then you can boot to the Recovery HD

Once you have booted from another drive you will have the option of running Repair Disk on the affected drive

If it still cannot repair the corruption then you will need to use another utility, I’d recommend DiskWarrior, it’s just under $100 but it can be invaluable in recovering a system affected by corruption, and if you were to take it into a shop then they would probably charge you more than that to resolve this anyway.

This uses a different method of repair by collecting data from the system and rebuilding the directory structure, there are warnings that it could result in data loss, and as with any kind of system repair there is always a risk of some data being lost, but I have used this program 12 times over the past 8 years and its worked 100%.

Repair Permissions

This is the most simple of maintenance tasks and one of the most overlooked, many people will take their machines to shops as they believe their machine has a serious problem, which can usually be fixed by this one task.

To do a permissions repair you have 2 options, using the Disk Utility app (recommended for most users), or using the command line, which is just as easy, but some people may not be that comfortable doing it this way.

So first, I’ll go through the Disk Utility method, this application is located in /Applications/Utilities

Double click on the application to start it up, now on the left hand side you will have a list of drives connected to your machine currently, on a MacBook Air you may only have your main hard drive listed, on a Mac Pro you may have several hard drives, a couple of SuperDrives, maybe some external USB drives etc.

The one you want to focus on is your system drive, this is usually the top one, but you want to click on the Volume, not the actual hard drive, the volume is usually just underneath with the same hard drive icon, but slightly indented from the edge, on a standard Apple installation this will be called Macintosh HD but it can be named anything.

Click on the Volume (Macintosh HD) and on the right hand side of the window you will have a few tabs, choose the First Aid one and at the bottom click Repair Permissions.

This will chug away for a while, if you do this regularly then it will only take a few minutes, but if you have never done it then it could take many hours.

Once done I’d recommend rebooting your machine and you should notice an improvement in performance, the reason for rebooting afterwards is I’ve found that quite often some applications or services that had issues starting up before the permissions repair
will end up in some sort of crashed state, so the repair won’t appear to have resolved anything, rebooting causes all of these items to restart and as they should now have the correct permissions and will be able to run correctly, thus not crashing, and not causing a system slowdown

Next I will run through the command line guide to this.

Open Terminal which is located in /Applications/Utilities


sudo diskutil repairPermissions /

this will prompt you for your admin password and will again chug away until done, you will recieve a better idea of its progress as it has a progress bar with a percentage completed, which the GUI option doesn’t have

All thats left to say is make sure you do this regularly, After every major software update or installation should be fine

I have done a video running through a Repair Permissions here