1. Clean Install Catalina From High Sierra
  2. Install Catalina From High Sierra


To get the latest features and maintain the security, stability, compatibility, and performance of your Mac, it's important to keep your software up to date. Apple recommends that you always use the latest macOS that is compatible with your Mac.

Learn how to upgrade to macOS Big Sur, the latest version of macOS.

  • So there may be a way easier way to set up Catalina as a guest on a Mac host, but at least this is something (happy to link to better tutorials if people post them). Install macOS High Sierra. I did a modified version of How to Install macOS High Sierra in VirtualBox on Windows 10 to get High Sierra installed on VirtualBox. These are the key parts.
  • If upgrading from macOS Sierra or later, your Mac needs 35.5GB of available storage to upgrade. If upgrading from an earlier release, your Mac needs up to 44.5GB of available storage. To upgrade from OS X Mountain Lion, first upgrade to OS X El Capitan, then upgrade to macOS Big Sur.

Check compatibility

Support Communities / Mac OS & System Software / macOS High Sierra. Updating High Sierra to Catalina. To consider that it needs more space to install and run. This video shows how to easily install macOS as a WM on an Unraid server.Easily install Catalina, Mojave or High Sierra.Please, if you can and want to suppor.

If a macOS installer can't be used on your Mac, the installer will let you know. For example, it might say that it's too old to be opened on this version of macOS, or that your Mac doesn't have enough free storage space for the installation.

To confirm compatibility before downloading, check the minimum requirements for macOS Catalina, Mojave, High Sierra, Sierra, El Capitan, or Yosemite. You can also find compatibility information on the product-ID page for MacBook Pro, MacBook Air, MacBook, iMac, Mac mini, or Mac Pro.

Related: Install macOS High Sierra on VirtualBox on macOS Catalina on Mac; There are two different ways to obtain macOS High Sierra ISO, first, create macOS High Sierra ISO file, second, download macOS High Sierra ISO, so we’ve prepared and shown it step by step beforehand. Here’s detailed steps on how to install macOS High Sierra on a hackintosh using the Clover method with the HFS Method. Apple introduced a new file system called Apple File System (APFS). When High Sierra is installed the drive is automatically converted over to APFS, but there is a way to disable it easily and keep the drive as HPFS by editing an XML file during the install. SAOImageDS9 is released once per year with beta versions available for download between major releases. Expand each sections to see the version of the operating systems which are currently supported. NOTE: Chrome users may have problems downloading from this page. Apple fixed the vulnerability in Big Sur 11.2.1, Catalina 10.15.7 and Mojave 10.14.6, but did not fix High Sierra and dropped support for that version. Software vendors have quickly followed suit and no longer support products on High Sierra which includes Microsoft Office 365 and Adobe CC 2021.

Make a backup

Before installing, 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.

Download macOS

It takes time to download and install macOS, so make sure that you're plugged into AC power and have a reliable internet connection.

Safari uses these links to find the old installers in the App Store. After downloading from the App Store, the installer opens automatically.

  • macOS Catalina 10.15 can upgrade Mojave, High Sierra, Sierra, El Capitan, Yosemite, Mavericks
  • macOS Mojave 10.14 can upgrade High Sierra, Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion
  • macOS High Sierra 10.13 can upgrade Sierra, El Capitan, Yosemite, Mavericks, Mountain Lion

Safari downloads the following older installers as a disk image named InstallOS.dmg or InstallMacOSX.dmg. Open the disk image, then open the .pkg installer inside the disk image. It installs an app named Install [Version Name]. Open that app from your Applications folder to begin installing the operating system.

  • macOS Sierra 10.12 can upgrade El Capitan, Yosemite, Mavericks, Mountain Lion, or Lion
  • OS X El Capitan 10.11 can upgrade Yosemite, Mavericks, Mountain Lion, Lion, or Snow Leopard
  • OS X Yosemite 10.10can upgrade Mavericks, Mountain Lion, Lion, or Snow Leopard

Install macOS

Follow the onscreen instructions in the installer. It might be 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.

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 macOS and related firmware updates.

Learn more

You might also be able to use macOS Recovery to reinstall the macOS you're using now, upgrade to the latest compatible macOS, or install the macOS that came with your Mac.

macOS installation problem happens all the time. After downloading the macOS installer, you try to install the macOS Catalina/Mojave, macOS Sierra or High Sierra but the installation get stuck. The progress bar has been stuck at 40% or something, showing: 'Installation is in progress. Calculating time remaining...'

If your macOS update also get stuck at 'Installation is in progress. Calculating time remaining...' Here shows you how to confirm if the installation is still going on and how to complete the update successfully.

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Clean Install Catalina From High Sierra

1.Check If the Install is Still Going on

Sometimes, it just takes a very long time for you MacBook or iMac to install the macOS Sierra or High Sierra update. So it doesn't necessarily mean that the macOS installation is frozen when the Mac stay at “20 minutes remaining” for two hours. And forcing restarting a Mac during OS installation may cause data loss. Therefore, before taking further action, press Command + L , which will open the log file and shows you if the installation is still going on and the amount of time left.

If you confirm that the installation is frozen, try the following methods to fix.

2. Force Restart Your Mac

Hold down the power button to power off the Mac. Then restart the Mac. After the Mac reboots, try to install the macOS Catalina, Mojave, High Sierra again.

If the installation get stuck when you try to update the Mac from Mac App Store, you may download macOS software from Apple website, which is the Combo updater which includes all the files required to update the macOS.

3. Install macOS in Safe Mode

Another way to install Catalina, Mojave, Sierra or High Sierra successfully is to install the macOS in safe mode. To get your Mac into Safe mode:

As you Mac start up, hold down the Shift key until the Apple logo appears.When you Mac is in Safe mode, go to App Store and get the High Sierra update.

4. Reset the NVRAM

If the Sierra or High Sierra installation is still won't complete in Safe mode, you can try to reset the NVRAM. NVRAM is a memory section on your Mac that store data like volume settings, screen resolution.

To reset the NVRAM on Mac, restart Mac and hold down Command + Option + P + R.The Mac will restart with options in NVRAM resetting. Now try to update your Mac.

Unable To Upgrade To Catalina From High Sierra

5. Reinstall macOS in Recovery Mode

This will help you to install macOS Sierra or High Sierra and newer versions, without data loss.

  • Restart your mac and hold down the Command + R to boot your Mac into Recovery mode.

  • Click Disk Utility and choose First Aid for your startup drive.

  • Restart the Mac again when this time, press Command + Option + R to get your Mac in Internet Recovery mode.

  • Choose Install a new copy of MAC OS and wait for the installation to complete.

If you have a Time Machine backup, restore your Mac from the backup in Recovery mode. After the restoration, try to install the macOS again.

6. Clean Install from External Drive

Can I Upgrade To Catalina From High Sierra

Install Catalina From High Sierra

Catalina

If none of the above methods work for your Mac, you can try to clean install the macOS Sierra or High Sierra from external drive. Here is the complete guide of how to clean install macOS High Sierra on Mac.

7. Recover Mac Files When Catalina/Mojave/High Sierra Installation Is Stuck

After fixing the frozen macOS installation issue, you may found some files missing on your Mac. If so, you can use FonePaw Data Recovery to recover the deleted data from Mac. The program can restore the missing documents, photos and more from hard drive, SD card, USB drive on Mac and Windows PC. Download the Mac version of FonePaw Data Recovery to have a try.

DownloadDownload

Step 1. Run the program.

Step 2. Select one or all categories: photos, videos, audio, documents, email or others. Then select the hard drive of your Mac. Click Scan.

Step 3. Once the scanning is stopped, you can view the deleted files and choose the needed one to recover to your Mac.

Should I Upgrade To Catalina From High Sierra

Imac Upgrade From High Sierra To Catalina

If the macOS installation on your Mac is still stuck or frozen, describe the problem below.