macOS Catalina gives you more of everything you love about Mac. Experience music, TV, and podcasts in three all-new Mac apps. Enjoy your favorite iPad apps now on your Mac. Extend your workspace and expand your creativity with iPad and Apple Pencil. And discover smart new features in the apps you use every day. Now you can take everything you do above and beyond.

Oct 26, 2017 Grab your borrowed Mac, head to the Mac App Store, search for Sierra, and click “Download.” When the process is done, the installer will launch—that’s okay, just close it with Command+Q. We don’t want to upgrade your friend’s Mac; we just need the downloaded files.

Check compatibility

1. Jun 07, 2019 I am borderline desperate to get Mac OS running on my high-end PC. A tech support acquaintance friend says running MacOS in a box on a PC can’t be done. I read your article with high hopes but no third party ever said they ever got a Mac app to run in the VirtualBox. Do you have some testimonials from third-parties saying they got it to work?
2. This is almost certainly a.dmg file that was not downloaded correctly. I was downloading.dmg files with chrome and could not get the system to recognize them. I switched to firefox and bingo! (My system is a macbook pro 2.3 GHz Intel Core i5 running Lion - but this may be irrelevant).

If you're using one of these computers with OS X Mavericks or later,* you can install macOS Catalina. Your Mac also needs at least 4GB of memory and 12.5GB of available storage space, or up to 18.5GB of storage space when upgrading from OS X Yosemite or earlier.

MacBook introduced in 2015 or later
MacBook Air introduced in 2012 or later
MacBook Pro introduced in 2012 or later
Mac mini introduced in 2012 or later
iMac introduced in 2012 or later
iMac Pro (all models)
Mac Pro introduced in 2013 or later

* To upgrade from Lion or Mountain Lion, first upgrade to El Capitan, then upgrade to Catalina. To find your macOS version, Mac model, memory, and storage space, choose About This Mac from the Apple menu . If your Mac isn't compatible with macOS Catalina, the installer will let you know. View the complete list of compatible computers.

Make a backup

Before installing any upgrade, it’s a good idea to back up your Mac. Time Machine makes it simple, and other backup methods are also available. Learn how to back up your Mac.

Get connected

It takes time to download and install macOS, so make sure that you have a reliable Internet connection. If you're using a Mac notebook computer, plug it into AC power.

Download macOS Catalina

If you're using macOS Mojave, get macOS Catalina via Software Update: Choose Apple menu  > System Preferences, then click Software Update.

Or use this link to open the macOS Catalina page on the App Store: Get macOS Catalina. Then click the Get button or iCloud download icon.

Begin installation

After downloading, the installer opens automatically.

Click Continue and follow the onscreen instructions. You might find it easiest to begin installation in the evening so that it can complete overnight, if needed.

If the installer asks for permission to install a helper tool, enter the administrator name and password that you use to log in to your Mac, then click Add Helper.

Why Can't My Mac Recognize Dmg For Virtualbox Windows 7

Allow installation to complete

Please allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac might restart, show a progress bar, or show a blank screen several times as it installs both macOS and related updates to your Mac firmware.

Stay up to date

After installing macOS Catalina, you will be notified when updates to macOS Catalina are available. You can also use Software Update to check for updates: Choose Apple menu  > System Preferences, then click Software Update.

Why Cant My Mac Recognise Dmg For Virtualbox Windows 7

Or get macOS Catalina automatically

If you're using OS X El Capitan v10.11.5 or later and your App Store preferences or Software Update preferences are set to download new updates when available, macOS Catalina will download conveniently in the background, making it even easier to upgrade. A notification will inform you when macOS Catalina is ready to be installed. Click Install to get started, or dismiss the notification to install later. When you're ready to install, just open the file named Install macOS Catalina from your Applications folder.

Learn more

• If the installer shows a list of apps that are not optimized for your Mac, learn about 32-bit app compatibility, then choose whether to proceed with the installation.
• For the strongest security and latest features, upgrade to macOS Catalina. If you have hardware or software that isn't compatible with Catalina, you might be able to install an earlier macOS, such as Mojave, High Sierra, Sierra, or El Capitan.
• You can also use macOS Recovery to reinstall macOS.

mac on virtualbox

Resources collected to launch a macOS on VirtualBox VM.

Getting started:

You need a macOS Installer ISO for High Sierraa which can only be created from an exsiting mac.
The one from App Store 'macOS High Sierra' installer is 19MB which cannot create bootable disks.
So you need get macOS High Sierra Patcher and download the full installer.
Now you'll be able to create a bootable ISO from the following.

Setting up the VM

• Clone this repo or you can just download the macOS.vbox file.
• Open the virtual machine from the repo, usually double clicking it will open the VirualBox GUI.
• Set the HighSierra.iso image created in Getting Started as a disk in the VM's optical drive.
• Create a new virtual hard disk. Make sure that you do not set the new virtual hard drive as an SSD, otherwise the High Sierra installer will format the drive as APFS, which is not yet recognized by VirtualBox's EFI BIOS and you will be unable to boot from the hard drive.
• Start the VM, and wait for the macOS installer to boot.
• Open Disk Utility, from the View menu enable the option to 'Show all devices', and erase the VirtualBox hard disk image.
• Quit Disk Utility, and install macOS to the newly initialized hard drive.
• When the installer completes, reboot. The VM will boot from the Optical drive; remove the disk from the virtual drive and reboot the VM.
• With the Installer ISO image not available to boot from, you will be dumped into the EFI Shell.
  Enter the following at the EFI prompt to boot macOS from the virtual hard drive and finish installation: FS1:'macOS Install DataLocked FilesBoot Filesboot.efi'
  Alternatively, you can enter exit at the prompt to go to the EFI BIOS boot screen, and use the Boot from file option to navigate to boot.efi.

Requirements

• The video memory has been set to 128MB, this is the max allowed by the VirtualBox VM, changing this isn't necessary.
• The RAM is set to 4GB, depending on your available RAM you may wish to increase or decrease the amount.

Installing updates

When installing patch updates like from 10.13.0 to 10.13.3 you'll have some trouble.
First of all make sure to have a snapshot before rebooting, so it won't download the installer again.
Then you need to boot from EFI shell since VirtualBox EFI doesn't automatically use the intended EFI.

• Press F12 repeatedly, so you get into the EFI shell.
• On the EFI shell, enter the following.
  FS1:'macOS Install DataLocked FilesBoot Filesboot.efi'

Setting Resolution

Resolutions to choose:
1280x720 | 1920x1080 | 2560x1440 | 2048x1080 | 3840x2160 | 5120x2880 | 1280x800 | 1280x1024 |1600x900 | 1440x900

Refrences:

Why Can't My Mac Recognize Dmg For Virtualbox Server

Adapted to macOS High Sierra (10.13) from :
geerlingguy/macos-virtualbox-vm licensed under MIT. See LICENSE_MIT
philipnewcomer/macOS-VirtualBox-VM licensed under GPL. See LICENSE_GPL
And various other sources

License

Why Cant My Mac Recognise Dmg For Virtualbox Mac

Dual licensed under MIT/GPL-3.0.