Download macOS Catalina ISO 

Install VirtualBox on Windows PC 

Install & Update VirtualBox Extension 

Create a New Virtual Machine & Customize it 

Run VirtualBox Code via Command Prompt 

Start the Virtual Machine 

Create macOS Catalina Bootable Disk 

Perform a Clean Installation of macOS Catalina 

On the welcome Wizard page, click Next. 

Keep the default setting on the Custom Setup page and click Next. 

Again Click Next to accept the default options unless you want to change something.  

On the warning Network interface page, just click Yes to process with Virtualbox installation. 

Click the Install button to install VBox. Again click Yes if required. 

While installing VBox, you might a security warning about “Oracle Corporation”. You need to click Install on this page to process with the installation. If you click Don’t install, the installation process will be terminate here and you can’t go ahead. If you see the security warning again click the Install button. 

Finally, click Finish. 
 

Open up VirtualBox, navigate to Tools>Pereferences>Extensions. 

Click on Plus (+) icon and select VirtualBox extension which you’ve downloaded at the beginning of this section. Click Install or Upgrade and then Agree to the terms and conditions. Click the OK button. 

Open up your VirtualBox application and click New. 
 

New VM 

Click Expert Mode and select the following options then click Create. 

Type a suitable Virtual Machine Name. 

Virtual Machine Location (a separate drive is recommended). 

Type (Mac OS X). 

Version (Mac OS X 64-bit). 

Memory 4 GB (recommended 8 GB or higher). 

Hard Disk: Select Create a virtual disk now. 

On the create virtual hard disk window, choose the following options. 

Disk Location: The default location should be fine unless you want to change to a new location. 

File Size: You can specify the disk size here. 

Hard disk file type: Select VHD  (Virtual Hard Disk) format. 

Storage on physical hard disk: Select the Dynamically allocated option. However, if you want to have a better performance disk then choose a fixed disk. Fixed disk, will allocate the specified size from your host machine immediately.  
 

It’s time to edit the virtual machine to make it works. Select macOS Catalina VM and click on Settings. Now, bring the following changes to macOS Catalina VM. 

Under System>Motherboard, increase the Base Memory to 12281MB. However, you can use a bit lower memory if your system doesn’t have this much RAM. 

Uncheck Floppy from the Boot Order section. 

Under the Processor tab, increase the processors to 4 or higher.  
 

On the Display window, increase the Video Memory to 128MB. 
 

From the Storage section, click on the Empty>DVD icon. Click on Choose a disk file. You should select macOS Catalina ISO which you’ve downloaded from the “Required Files” section of this post. Finally, click OK to close the macOS Catalina Settings window. 
 

When you opened VirtualBox code via notepad or any other text editor, use the replace function of the program to Replace the “VM Name” with your virtual machine name. See the picture below to get an idea of how to do it. 
 

Now, you’ve two choices. First, if you want to fix your macOS Catalina screen resolution in the first place. You should also execute the following code. You have to change “VM Name” with your virtual machine name and HxV with a screen resolution such as “1280×720“.  

Important Note: We highly recommend to quit the VirtualBox program before executing the code. If you don’t do it, your virtual machine might not proceed to the installation step. 
 

Once you replaced the “VM Name” with your virtual machine name, then run the code one by one via command prompt (CMD). You can open the command prompt by pressing the Windows+X key in Windows 10 and select Command Prompt from the list. Or simply press Windows key and type CMD. Click Run As Administrator and click Yes. 
 

Once you start your VM, a whole bunch of code will run on the screen, but you should not be worried about it. Wait for a few minutes, and you should see the macOS Catalina Language window. Select your Language and click Continue arrow. 
 

Background Code 

Choose A Language 

Now, you’ll see macOS Utilities Window. From the list, select Disk Utility and click Continue. 

Select your main VHD Disk and click the Erase button. Choose the following options and again click Erase. 

Name: Catalina Disk (You can type any name you want) 

Format: APFS (If you get an error, select Mac OS X Extended Journaled) 

Scheme: GUID Partition MAP 

Now, close the Disk Utility window. 
 

Catalina Disk Utility 

Erase Catalina Disk 

From macOS Utilities, select Install macOS and click Continue. 

Click Continue on Install macOS Catalina screen. 
 

macOS Catalina Utilities 

macOS Catalina Setup Process 

Agree to the macOS Catalina License agreement.  

Select macOS Catalina Disk and click Install. 
 

Agree to the Terms and Conditions 

Select Installation Disk for Catalina 

Now, wait for 3 minutes and your VM will restart. macOS Catalina will be installed on your Disk. Next, you should not do anything. You’ll see another 29 minutes installation window. 

Once you’ve passed the step #9. You’ll see the macOS Catalina Welcome window. Select the following options. You can change most of the settings later on, so don’t worry about it for now. 

Select your Country and click Continue. 

Choose a Keyboard Layout and click Continue. If you’re not happy with default settings, you can customize the Settings. 

On the “Data & Privacy” window, click Continue. 

Select Don’t transfer any information now. 

Click on Set Up Later then Don’t Sign In. Click Skip. You can add your Apple ID later. 

Click Agree to the Terms and Conditions and click Continue. 

Fill out the Full name,  Account name, Password, and Hint then click Continue. 

If you want to customize Express Set Up, you can click on Customize Settings otherwise click on Continue. 

On the Analytics window, click Continue. 

On-Screen Time, click Set up Later. 
 

Create Catalina Computer Account 

Catalina Screen Time 

Do not set up Siri for now. Just skip it. 

Select an appearance theme and click Continue. You can choose between dark mode or light and Auto mode. 
 

Choose Catalina Theme 

Wait a few seconds that your macOS should be set up. 

Close Feedback Assistant for now and close mouse & keyboard window. 

 Well done 👌 you’ve successfully installed macOS Catalina on VirtualBox using the ISO image.