If you’ve installed macOS Mojave to take it for a test drive and decided you don’t like it, or it doesn’t work with some of your apps, and you want to downgrade from Mojave to High Sierra, the good news is that it’s possible. The bad news, though, is that it’s quite a long process with lots of different steps. We recommend that you read the guide below carefully before you start.

Do you really need to downgrade?

If you’ve decided to downgrade because Mojave is running slowly, you could try improving its performance first, by getting rid of unwanted files. CleanMyMac X scans for junk files, such as those created by iTunes, the Photos app, and the Mac’s own system software. You can then preview what it’s found and recommends you delete and decide for yourself what you want to get rid of, or you can just press a button and have it delete everything it’s found. You might find that just by deleting these file, performance improves considerably. Moreover, the app has a special Optimization and Maintenance tools designed to improve your Mac's speed. You can get started with CleanMyMac very quickly by downloading it here (for free).

How to downgrade from macOS Mojave to macOS High Sierra

Jan 15, 2018  I had the same problem with permissions/desktop files disappeard after updating my system to High Sierra. Steps that worked for me: 1. Create another administrator account (u cant do below steps from your corrupted account) 2. Log to the new account. Go to /users right click on the corupted user folder and select Get Info. Jun 14, 2016  Of course to use any of this, your Mac must be able to run macOS Sierra. Not all will. While Mac OS X 10.11 El Capitan could run on some systems dating back to 2007, macOS Sierra.

If you've decided that you still want to go back to High Sierra, follow the steps below. And please note that the process of downgrading is quite complicated and time-consuming, so try to be patient.

Step 1: Back up your Mac

You should back up your Mac before you start any major process, and hopefully you backed up before installing Mojave. If you’re unsure how to back up your Mac, you can follow the steps in this article. However, any files you’ve used or been working on since you installed Mojave won’t be up to date on that back up, so you need to copy those to an external disk or a cloud storage service like iCloud Drive or Dropbox. Don’t do anything else until you’ve copied those files.

Step 2: Make notes

The process of downgrading wipes everything from your hard drive, including passwords, license keys and settings. If you have a backup of your Mac from before you upgraded to Mojave, you should be able to migrate much of that data back to your Mac once you’ve reinstalled High Sierra. However, it’s a good idea to make sure you have a note of all the passwords, settings, licence keys and other data you’re likely to need. If you use a password manager that syncs with other devices, you could use that to store all the data you need. Otherwise, any cloud-based note-taking tool that encrypts notes will do.

It’s also a good idea to make screenshots of settings, to make it easier to set them back up later on. You should store these on an external disk, or cloud storage space.

Step 3: Erase Mojave

Once you’ve backed up the files you’ve worked on since installing Mojave, and created the bootable installer, it’s time to erase Mojave.

1. Make sure your Mac is connected to the internet.
2. Click on the Apple menu and choose Restart.
3. Hold down Command+Option+Shift+R to boot into recovery mode. Note, you can also boot into Recovery mode by pressing Command+R. However, adding Option+Shift will allow you to reinstall High Sierra, if your Mac came with it installed.
4. Click on Disk Utility in the macOS Utilities window.
5. Select the disk with Mojave on it.
6. Choose Erase.
7. Give the disk a name, choose Mac OS Extended (Journaled) or APFS as the file format.
8. Click Erase.
9. Quit Disk Utility.

How to downgrade from macOS Mojave if your Mac shipped with High Sierra

1. Erase your startup disk as described above — you need to do that first because Recovery mode won’t install an older version of the OS over a newer version.
2. From macOS Utilities, choose Reinstall macOS.
3. Press Continue.

How to downgrade from a Time Machine backup

If you made a backup of your Mac just before installing Mojave, you’re in luck. You can use that to reinstall High Sierra. Make sure your Time Machine disk is connected to your Mac, either directly or over a network, before you start.

1. Erase your startup disk, as described above.
2. In the macOS Utilities window, choose Restore from Time Machine Backup.
3. If your backup is on an external disk, select it. If it’s on a Time Capsule or network disk, select it and choose Connect to Remote Disk.
4. Type in your name and password for the disk, if necessary.
5. Select the date and time of the backup you want to restore to.
6. Follow the onscreen instructions.

How to downgrade using a bootable High Sierra installer

If your Mac didn’t ship with High Sierra and you don’t have a Time Machine backup, you’ll need to create an installer disk. Apple used to make all previous versions of macOS available in the Purchased tab of the Store, but the most recent version there now is El Capitan.

If you’re downgrading before the full public release of macOS Mojave, High Sierra is still available in the App Store. You can find it on the left hand side of the main App Store window, or by search for it.

Note: If you want to downgrade Mojave after its final release and haven’t already created a bootable installer of High Sierra, you’re out of luck. You’ll have to create a bootable installer of El Capitan or use Recovery Mode to roll back to the most recent version of macOS installed on your Mac. To do that, use Command+Option+R when you boot into Recovery mode (see Erase Mojave, above) instead of Command+Option+Shift+R. For that reason, if you’re reading this before Mojave has been released, it’s worth downloading High Sierra now, just in case.

Click the Download button on the App Store page and wait for the OS to download. If the installer automatically launches when it’s downloaded, quit it.

1. You’ll need an external hard disk or SSD, or a USB stick that’s at least 12GB to create the installer.
2. Plug the external drive or USB stick into your Mac.
3. In the Finder, click on the Go menu, select Utilities.
4. Launch Disk Utility from the Utilities folder.
5. Click on the external disk in the sidebar and choose the Erase tab.
6. Give the drive the name ‘MyVolume’ in the Erase window, set the format to Mac OS Extended (Journaled) or APFS.
7. Click Erase.
8. Press Done when it’s finished.
9. Quit Disk Utility.

Go back to the Utilities folder in the Finder and this time, launch Terminal.

1. Type the following command: sudo /Applications/Install macOS High Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install macOS High Sierra.app
2. Hit the Return key.
3. Type in an administrator account password for your Mac.
4. Wait for the word ‘Done’ to appear in the Terminal window.

Step 4: Reinstall High Sierra

1. Go to the Apple menu, choose Restart, and hold down the Option key.
2. When the option to select a boot disk appears, choose the installer disk you just created.
3. High Sierra will begin installing on your Mac.
4. When it’s finished, your Mac will restart and Startup Assistant will appear.
5. Go through the steps to set up your Mac.

Step 5: Restore settings

If you made a non-Time Machine backup of your Mac before installing Mojave, you can use the backup tool to restore your Mac to the state it was in when you made the backup.

Otherwise, you’ll need to reinstall apps manually, using the notes you made earlier to enter licence codes and re-create settings. You can also copy back files that you backed up when you were running macOS Mojave.

How to keep your fresh installation clean

You’ll notice when you revert to a clean installation of High Sierra, that your Mac seems to be running more quickly and encountering fewer problems than it did previously. Part of the reason for that is that, as you use your Mac, it accumulates lots of temporary files, cache files and other ‘junk’ that can cause performance and compatibility problems.

It could also be because your previous installation, along with all the files and applications you had installed, was occupying more than 90% of your Mac’s startup drive. MacOS uses your startup drive to store data temporarily, as a proxy for keeping it in RAM. If you don’t have enough free storage space, you will start to see performance problems.

The solution is to regularly clear out junk files and to audit your Applications, uninstalling any you no longer use. We recommend CleanMyMac X for both tasks. CleanMyMac makes it easy to uninstall apps with a couple of clicks. And when it does so, it doesn’t just remove the application itself — which is what happens if you just drag it to the Trash — it also tracks down and removes all the application’s associated files in your user Library and gets rid of those too.

As you can see, downgrading from Mojave to High Sierra could be quite simple or it could be a long drawn out process, depending on you do it. If your Mac came with High Sierra, you’re in luck, because you can use Recovery Mode to roll back — though you’ll need to erase your startup disk first. Likewise, if you have a Time Machine backup of your High Sierra installation just before you installed Mojave. If neither of those applies, your only option is to create an installer disk from the App Store. Whichever method you use, once you’ve reinstalled High Sierra, it’s worth using CleanMyMac (get its free version here) to keep your clean installation fresh and performing as well as it can.

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The newest version of Apple’s desktop operating system, macOS High Sierra, was launched on September 25. It’s not a huge release in terms of new features, but there are a few things that can make your life easier.

These are the best 17 features, tips, and tricks for macOS High Sierra. Let's discover.

What are the new features in macOS High Sierra?

The biggest changes in High Sierra aren’t even user-facing features. But while you may not notice these changes, they should make your Mac more efficient, which can save you battery life as well as speed up tasks.

APFS, a new file system

If your Mac has all-flash storage (an iMac with an SSD, or any recent Apple laptop), High Sierra will bring with it a new file system called APFS, or Apple File System. It’s a 64-bit architecture with built-in encryption and designed to speed up common tasks like copying big files. If your Mac has a Fusion drive or a traditional spinning hard drive, you won’t get APFS right away. This is a pretty under-the-hood improvement that most users probably won’t notice.

HEVC video encoding

With iOS 11, iPhones and iPads are saving videos in HEVC format, or High Efficiency Video Codec, also known as H.265, since it’s the successor to H.264. HEVC support comes to macOS High Sierra as well. That way, videos you shoot with your iPhone stay in HEVC format when you transfer them to a Mac, which keeps HEVC’s superior compression intact. HEVC compresses video files up to 40 percent more without losing quality, which is a big deal considering how many devices shoot in 4K these days. Still, this is also an under-the-hood improvement that won’t

Photos for Mac

Apple’s Photos application gets a big overhaul in High Sierra. For example, the new always-on sidebar making it much easier to find what you’re looking for. But aside from handy interface tweaks, Photos has some very useful new features too.

New editing features

It’s also got a new Curves feature in the editing panel, which is a lot more intuitive than the Curves feature in Photoshop. A new Selective Color feature lets you saturate just one color, if you want to make your subject’s eyes or lipstick, for example, really pop.

Live Photo effects

When you take Live Photos with an iPhone, the camera captures three seconds of video. Starting in iOS 11, the Photos app can convert those into three new Live Photo types: Bounce is kind of like Instagram’s Boomerang, showing the same action backwards and forwards. Loop is like a GIF that plays over and over forever. And Long Exposure is good for nature shots and landscapes, smoothing out any moving parts like a rushing river or a highway full of cars. The same Live Photo effects are supported in High Sierra on the Mac, and they’re nondestructive, so you can try out an effect on any Live Photo without altering the original.

Live Photo editing

You can also edit a live photo to trim off any unwanted parts, and select the key frame from any frame of the video. This is great if you take Live Photos of people—if, for example, someone has her eyes closed in the key frame chosen by default, you can drag the selector box around to find a frame where everyone is actually looking at the camera.

Third-party editing

High Sierra makes it easier to use Photos to organize your photo collection, but still send them off to another app for editing. You can right-click a photo in Photos and choose Edit With from the contextual menu to open that photo in another editor like Photoshop and Pixelmator—or even Setapp apps like CameraBag Pro and Tayasui Sketches.

Third-party services

Photos always had Apple’s own print products like books and cards, but in High Sierra, you can also create new projects with third-party services like Shutterfly, WhiteWall, iFolor, Wix.com, Mpix, and Mimeo, from right inside the Photos app. This will give you more choices and different projects, like framed prints, wall decals, websites, and more.

Upgrades to Safari

Apple’s own web browser works even harder in High Sierra to keep annoying ads and autoplay videos from driving you bananas.

Intelligent Tracking Prevention

You know how after you shop for something online, you keep seeing that same thing advertised everywhere else you go? Safari will use machine learning to keep advertisers from tracking your behavior, while letting useful cookies stick around. You can turn this off in Safari’s preferences if you like, but it might be nice to not have the things you buy online haunt you for weeks on end.

Auto-play videos only on your terms

Everyone who browses the web has been annoyed by an auto-playing video. You’re trying to read an article, and then boom, all of a sudden there’s a commercial blaring in the sidebar, and it ruins the experience. Then again, when you visit sites that make good videos, you might not mind. In High Sierra, you can block auto-play videos by default but still white-list your favorite sites. I can never get enough of those recipe videos, myself.

Personalize the settings per site

Safari for High Sierra also lets you enable content blocking pkug-ins per site, or have a site default to Reader mode to make it easier to see. If one of your favorite blogs uses a really small font, you can even zoom its pages by default. If your local newspaper’s site is always pestering you to share your location, you can disable that for the site too. Just right-click the site’s name in the URL bar and choose Settings for This Website to customize it all.

The little things

There are more bells and whistles around macOS High Sierra too, such as…

Better Siri

Siri gets a more natural speaking voice in High Sierra. It also uses machine learning to learn what kind of music you like to listen to—try asking for something to fit your mood. With the HomePod coming this holiday season, Apple is putting a big emphasis on Siri’s musical knowledge across macOS and iOS too.

Top Hits in Mail

Mail in High Sierra gets a Top Hits feature that surfaces your most important mail based on how often the sender emails you, how often you read that person’s email, and if you’ve marked them as a favorite or VIP.

High Sierra Mac

Track flights with Spotlight

You know how you can Google a flight number and find out information about its departure time, on-time status, and so on? Now Spotlight in macOS High Sierra can tell you that too. Type Command-Space to open Spotlight, or paste the flight number into Safari’s URL bar.

FaceTime snapshots

You can take a picture during a FaceTime chat in High Sierra, but your partner will get a notification that you did.

iCloud sync for Messages

High Sierra Mac App Store

Messages are now synced between iOS 11 and macOS High Sierra using iCloud. That way if you have to restore your Mac or your iPhone you won’t lose your Messages history, plus read/unread status will match across all your devices.

Pinned notes and tables in Notes

Apple’s Notes app got a little more useful with the addition of tables, and the ability to pin important notes to the top of your list. Notes already syncs perfectly with iOS via iCloud, and you can add webpages and photos to Notes easily from the Share menu all around macOS and iOS.

Share iCloud storage

Before High Sierra, you had to pay for separate iCloud storage space for every member of your family who wanted it. Now you can get a 200GB or 2TB plan and share it among everyone in your iCloud Family Sharing group.

Enjoy new macOS and be among the first ones who get the new exciting features.

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