MAC OSX Create Bootable USB Installation Media

Here is the command to create a bootable installation USB for the latest OSX 10.12 Sierra, it’s the same as previous releases, at least as far back as Mavericks 10.9 with the only change being the name of the (“Install macOS” in this case) and the name of the USB volume I’m writing to (“SierraInstaller” in this case).


sudo /Applications/Install\ macOS\ --volume /Volumes/SierraInstaller --applicationpath /Applications/Install\ macOS\ --nointeraction &&say Done



Mac OSX Yosemite & iCloud Failures

The Analysis

I received a report from an OSX Yosemite user who found documents saved on their iMac had stopped synchronizing to iCloud as they weren’t visible there or on the user’s MacAir.

Inspection showed the files in question had a grey dotted cloud next to their name in finder.

The Tests

Documents created on the MacAir were synchronized back to the iMac so iCloud was working to some degree.

Creating a new document on the iMac resulted in the grey dotted cloud next to the document but nothing in the iCloud web interface.

Using the following command to inspect the “bird” daemon log indicated a fault with an alias file, locating that file I discovered it pointed to a non-existent file.

brctl log -w

I moved the broken alias out of the iCloud drive and the errors disappeared from the log but nothing appeared to be synchronizing.

I took a backup of the data (in addition to the Time Machine backup that is in permanent operation).

I then :

  1. Stopped the “bird” daemon with “killall bird” on the terminall
  2. Moved the “~/Library/Mobile\ Documents” folder to the desktop (“~/Desktop/Mobile\ Documents”)
  3. Renamed the database store folder for the iCloud service “~/Library/Application\ Support/CloudDocs/”
  4. Moved the folder from step 2 (“~/Desktop/Mobile\ Documents”) back into place at “~/Library/Mobile\ Documents”
  5. Rebooted the iMac and waited 12 hours (overnight).

The next day I inspected the machine and found around 40% of documents appeared to have re-synchronized, 10% had the dotted grey cloud and the remaining 50% had lost their file icon and instead had a dotted grey square for an icon!

I looked at Activity Monitor and inspected the “bird” process, it had read and written over 30GB of data to the disk, considering the user’s iCloud drive was around 3GB in use this seemed odd.

I restarted the iMac and waited a further 6 hours, upon returning all files had synchronized successfully and everything was well!

MAC OSX Uncategorised

Create El Capitan 10.11 USB Installer Disk

  1. Download the installer from the App Store but do not install it, close the installer when it launches
  2. Format an 8GB+ USB Drive in the GUID type and Journaled (not case sensitive) partition
  3. run the command (where Untitled is the name of the partition you created in step 1):
    sudo /Applications/Install\ OS\ X\ El\ --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ El\ --nointeraction
  4. Sit back and relax, smoke a pipe while you wait maybe

Mac OSX dd Disk Read / Write

dd bs=512 if=/dev/rXX# of=/some_dir/foo.dmg conv=noerror,sync

Hardware MAC OSX

Oracle Virtual Box Mac OSX Physical Disk Attachment

1. Get the identity of the physical disk using
“diskutil list”
from the command line. Usually it’s named “System” if booting from an OSX Live USB drive

2. Unmount the physical disk from the system

3. From terminal create a holding VMDK file for Virtualbox to communicate with the physical disk through by:
“sudo VBoxManage internalcommands createrawvmdk -filename <<DIR/FILE.vmdk>> -rawdisk /dev/disk<<#>>”

4. Correct permissions on both the physical disk and the file you created, something like:
“sudo chmod 777 /dev/disk<<#>>”
“sudo chown <<group>>:<<user>> <<DIR/FILE.vmdk>>”
“sudo chmod 770 <<DIR/FILE.vmdk>>”

5. Launch Virtualbox, create a new DOS VM and attach a SATA Controller and then the new VMDKfile as a SATA disk

6. From Virtualbox “File>Virtual Media Manager”, modify the <<DIR/FILE.vmdk>> so that it’s set as a “writethrough” disk

7. Then attach the desired boot cd to the VM and ensure the boot order is correct

8. Start the VM!

MAC OSX Networking



To add an additional IP to a network interface on OSX using the GUI simply “replicate service” on any interface via the cog in [Network Settings] and then assign the IP to the replicated interface manually.


From the terminal:

sudo ifconfig en1 inet netmask alias

Where sudo = execute as root, en1 = the interface you want to add an alias to, = ip you wan to add, = desired netmask.


Mac DNS Reset