ClearOS USB Installer

This guide will help you burn your ClearOS 7 (all versions) ISO to USB. If you are using an older version of ClearOS or the ClearOS 6.7.0 ISO, please use this guide. This guide is also applicable for the 6.6.1 ISO but not for 6.7.0.


You will need a system or program that has the ability raw write the ISO to USB. For Linux and Mac, the 'dd' program is perfect for the task and already exists on your install.

Download the ISO for ClearOS.

Open a terminal program. Plug in the USB device and determine the raw name for the disk.

WARNING!!! Be advised if you select the wrong disk, you can effectively destroy data on your existing operating system. Be sure to use the RIGHT device name. I'll put more warnings throughout the document in case you didn't read this one or believe me that this will really make you hate the fact that you ever found this howto.

Optional Security Recommendation

To validate you downloaded the right thing and that it valid and not compromised, you can and should run an SHA256 sum on the file. What that means is that we've included in the ISO directory a text file that has some information about the ISOs we have provided. This file can be accessed or listed by opening it with notepad or concatenated at command prompt to see its contents. For example:

DAVIDs-MBP-5:~ dloper$ cat ~/Downloads/ClearOS- 
# The image checksum(s) are generated with sha256sum.
a8767efc63ad3a118de3459f94ef20aee967ef4a5487af6b11eb111b150ba6f4 *ClearOS-DVD-x86_64-
5a953cb34a8a9f5f9cd9baf4fead46c89a72c5927f0627b2e86a69a23feecaa3 *ClearOS-netinst-x86_64-

These 'codes' are nothing more than a mathematical sum of all the data bits of the ISO. The reason why we provide this is because you can use this number to validate whether or not the ISO we have produced matches the ISO you have in your Download folder. If you do not trust the checksum available in the same folder of the Download then you can ALSO validate it against the release notes for the version of ClearOS you are running.


Find the USB disk

To know exactly which partition is your USB, Launch the 'Terminal' program under the Utilities Folder under Applications. Run the following:

ls /dev/disk*

This will show your your listed drives. Insert the USB drive and run it again.

ls /dev/disk*

Here I can see that my disk is /dev/disk1. It may be /dev/disk2 or something completely different.

Davids-MacBook-Pro-2:Downloads dloper$ ls /dev/disk*
/dev/disk0	/dev/disk0s1	/dev/disk0s2	/dev/disk0s3
Davids-MacBook-Pro-2:Downloads dloper$ ls /dev/disk*
/dev/disk0	/dev/disk0s1	/dev/disk0s2	/dev/disk0s3	/dev/disk1

You can also validate the disk by running the following and verifying the size:

diskutil list

Again, it is really important that you identify your correct disk. If I do the dd command against /dev/disk0, I'll destroy my Mac's main drive.

Unmount the disk so we can raw write to it

When you insert your USB drive, your Mac will try to mount it. We need it unmounted before we can format and write our image to the drive. Under Applications, open the Utilities menu. Launch the 'Disk Utility' program and keep the 'Terminal' program.

In Disk Utilities, highlight any existing partitions under the main device and Unmount them using the button above.

Another way to unmount it from command line is to run the diskutil to unmount the name you discovered in the previous step. For example:

diskutil unmountdisk /dev/disk2

Write the data to USB

Change directory (using the 'cd' command) to the location of your ClearOS ISO folder, for example (change 'myuser' to your user. If you need to see the list of users, type 'cd /Users/' and then hit tab twice.):

cd ~/Downloads/

Using the 'dd' command, write the ClearOS image to the USB drive (Change the ISO name to the one you downloaded and change the device name to the one you found on the list (ls /dev/disk*) earlier). You will also want to put an 'r' in front of the device type because it writes faster and more complete on Mac. DON'T COPY and PASTE HERE, structure the command properly. I'll give some examples:

Writes ClearOS Professional 6 to disk2

sudo dd if=clearos-professional-x86_64.iso of=/dev/rdisk2 bs=1024000

Writes ClearOS to disk3 sudo dd if=ClearOS-DVD-x86_64- of=/dev/rdisk3 bs=1024000 Writes the current version of ClearOS 7 to disk 2 **

sudo dd if=ClearOS-DVD-x86_64-7.2.0.iso of=/dev/rdisk2 bs=1024000
Just an additional warning, the above command can utterly ruin your day if done wrong. If you are just mindlessly copy and pasting the above, you are doing it wrong. Be sure to to specify the correct disk for the output file ('of') parameter. It might be disk1 but it can be totally different. Check again. Once more please. Yes, you can phone a friend. Is that your final answer?

You will be prompted to provide your password for your username to make this change since it has the potential of damaging your computer. If all goes well, you will have put the image to your USB. If you did it wrong and pushed the image to your Mac's hard drive, I'm sorry, I tried to warn you.

You will know that it is done when it gives your command prompt back.


The install process to USB is similar to that of the Mac. You can use 'wget' or 'curl -o' to download the package and then 'dd' it to your USB drive. When you insert the drive you can use the following to determine the correct drive:

fdisk -l | grep Disk

Once you know the drive you will use, you will reference it in the next command for the 'of' parameter.

dd if=clearos-professional-x86_64.iso of=/dev/devicename bs=1024000
As with the Mac instructions, I will be very sad but have to tell you repeatedly 'Sorry' and that there is nothing I can do to recover your system if you do this command to the wrong drive. Just sayin'.


You can use a program like WinDD or dd for Windows to write the file to USB.

Something like this…maybe?

dd if=clearos-professional-x86_64.iso of=\\.\Volume{6f41f4b2-d11a-11de-b318-001d4f88486c}

dd for Windows

Download and extract the dd zip file and then place the executable in your C:\Windows\ directory. Make sure that you insert the USB drive but close any applications that might open up the volume.

Open a command prompt (Start » Run » cmd)

In the command prompt, run the following to get a list of your drives:

dd --list

You should get an output such as this:

C:\Users\Username>dd --list
rawwrite dd for windows version 0.5.
Written by John Newbigin <>
This program is covered by the GPL.  See copying.txt for details
Win32 Available Volume Information
  link to \\?\Device\HarddiskVolume4
  fixed media
  Mounted on \\.\d:

  link to \\?\Device\HarddiskVolume5
  removeable media
  Mounted on \\.\f:

  link to \\?\Device\HarddiskVolume2
  fixed media
  Mounted on \\.\c:

  link to \\?\Device\HarddiskVolume1
  fixed media
  Not mounted

  link to \\?\Device\SftVol
  fixed media
  Mounted on \\.\q:

  link to \\?\Device\CdRom0
  Mounted on \\.\e:

NT Block Device Objects

Virtual input devices
 /dev/zero   (null data)
 /dev/random (pseudo-random data)
 -           (standard input)

Virtual output devices
 -           (standard output)

In this case, my USB device is 'F' and the volume label is:


Then run the dd program to image the ISO image to the disk.

dd if=C:\Users\Username\Downloads\ClearOS-DVD-x86_64.iso of=\\.\Volume{4268772a-e552-11e5-868d-e89a8f45233b} bs=1M

Alternatives for Windows

content/en_us/kb_o_clearos_usb_installer.txt · Last modified: 2020/07/30 07:20 by