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Want a Flawless Way to Create a Bootable Disc on Mac? The Ultimate Guide to Making an ISO from a Folder.
You need to get files onto a server. The server has no internet. This is a common problem. You have access through a special tool, like iLO or iDRAC, that lets you connect a virtual CD or DVD drive. If you can bundle your files into a single .iso file, you can solve this problem. An ISO file acts just like a real disc.
But how do you make an ISO file on a Mac? It seems hard, but it is not. Your Mac already has the tools you need. You do not need to download anything new. The process uses two simple steps. First, you will use an app called Disk Utility to make a special kind of file called a CDR image. Second, you will use the Terminal to change that CDR file into a standard ISO file that any computer can use.
Why an ISO is a Great Solution
An ISO file is a perfect copy of a disc. Think of it as a digital version of a CD, DVD, or Blu-ray. It holds all the files and folders in one neat package. This makes it very useful for a few reasons:
- Works Anywhere: ISO is a universal format. Windows, Linux, and macOS all understand it.
- Keeps Everything Together: It locks your file and folder structure in place. Nothing gets accidentally moved or renamed.
- Perfect for Virtual Machines: It is the standard way to install operating systems or software on virtual machines and remote servers.
Step 1: Create a CDR Image with Disk Utility
The first step is to take your folder of files and turn it into a master disc image. The format macOS uses for this is .cdr.
- Open Disk Utility. You can find this app in your Applications folder, inside the Utilities folder. An easy way to open it is to press Command + Spacebar to open Spotlight, type “Disk Utility,” and press Enter.
- Go to the Menu. At the top of the screen, click on File. A menu will drop down.
- Find the Right Option. From the File menu, move your mouse to New Image, and then click Image from Folder….
- Choose Your Folder. A window will pop up asking you to select the folder you want to turn into an image. Find the folder that holds all your files, click on it once to highlight it, and then click the Choose button.
- Set the Image Format. You will now see a “Save As” window with several options. This part is very important.
- Find the dropdown menu labeled Image Format.
- Change it to DVD/CD master. This creates the .cdr file we need.
- Save the File. Give your file a simple name and choose a location to save it. The Desktop is a good, easy-to-find place. Click the Save button.
Disk Utility will now work on creating the image. When it is finished, you will see a new file on your Desktop with a .cdr extension.
Step 2: Convert the CDR to an ISO with Terminal
Now you have a .cdr file. This is a Mac-only format. We need to convert it into a universal .iso file. For this, we use the Terminal app.
- Open Terminal. You can find it in the same Utilities folder as Disk Utility. Or, use Spotlight (Command + Spacebar) and type “Terminal.”
- Go to Your Desktop. The .cdr file is on your Desktop. You need to tell the Terminal to work in that location. Type the following command and press Enter:
cd ~/Desktop
- Run the Conversion Command. This is the command that does all the work. It uses a tool called hdiutil, which is a powerful command for handling disc images on macOS. Let’s say you saved your CDR file as MyFiles.cdr. You want to create an ISO file named MyFiles.iso. You would type this command and press Enter:
hdiutil makehybrid -iso -joliet -o MyFiles.iso MyFiles.cdr
Let’s break down what that command means:
- hdiutil: This is the name of the tool.
- makehybrid: This tells the tool you want to make a hybrid image that works on different systems.
- -iso -joliet: These are flags that set the format. ISO 9660 is the standard format, and Joliet allows for longer filenames that work well with Windows systems.
- -o MyFiles.iso: This sets the name of the output file.
- MyFiles.cdr: This is the name of the input file you are converting.
After you run the command, a new file named MyFiles.iso will appear on your Desktop. That’s it. You now have a standard ISO file ready to be used as a virtual CD/DVD on your server or any other system. This simple, two-step method is a powerful skill for anyone who manages servers or works with virtual machines.