Parts 1Downloading the Things You Will Need

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Set at least 2 CPU cores for the macOS. Click and drag the slider bar below "Processor(s)" to set the number of processor cores you want to allocate towards the macOS virtual machine. The more cores you can allocate, the better it will run. It's recommended you allocate at least 2 cores.

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  The red line above the slider bar indicates how many CPU cores are needed for your current operating system to run. To avoid performance issues, do not drag the slider bar past the green line.
  
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Click Display in the menu panel to the left. This opens the Display menu for the virtual machine.

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Allocate at least 128 MB of video memory. The "Video Memory" slider bar is at the top of the menu. Click and drag the slider to allocate video memory. You can also type the amount of video memory you want to allocate in the box to the right. Make sure you are allocating at least 128 MB of video memory.

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Click Storage and ensure "Use Host I/O Cache" is checked. The "Storage" menu option is in the menu bar to the left. Click the "Storage" menu option and ensure the checkbox next to "Use Host I/O Cache" is checked. If it is not, click the checkbox to check it. This allows the macOS to cache the image file itself. This results in better performance.[5]

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10
Load the macOS Big Sur iso file into the empty optical drive. Use the following steps to load the macOS Big Sur iso file you downloaded into the empty optical drive:

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  Click Empty below "Storage devices."
  
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  Click the CD icon next to "Optical Drive" in the top-left.
  
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  Click Choose a disk file.
  
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  Navigate to and select the macOS 11.0 Big Sur ".iso" file.
  
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  Click Open.
  
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