Oct 09, 2019  Way back in High Sierra, Apple started warning us that certain apps were no longer compatible and would stop working in future. That future arrived with the macOS Catalina update. Oct 09, 2019  Apple started warning Mac users about plans to end support for 32-bit apps back with macOS High Sierra. In High Sierra, users started getting warnings about a 32-bit app's.

You got really excited about the new operating system from Apple and installed macOS 10.13 High Sierra right away. However, what you initially thought to be a great idea, turned out to be overkill. Now you wish things could go back to the way they used to be, and you feel nostalgic about the days when your Mac was happy with macOS Sierra. Is it too late? Can you return to the way things were?

Of course, don’t sweat it. Here’s a simple guideline on how to downgrade from macOS 10.13 High Sierra to macOS 10.12 Sierra. And if you ever want to get back, that’s possible as well!

Why should you downgrade to macOS Sierra?

Whatever your reasons to downgrade, we’re here to assist you. But here are a few of the issues that are most likely to point you to this radical decision:

1. The macOS High Sierra Beta is too much for you to handle

High Sierra Mac App Store

You knew that the Beta version had a risk of issues and bugs, but you didn’t expect it to be so complicated and thought you could take it. Tough luck, you have to admit you cannot take it. And why should you? Apps seem to have gone mad, giving themselves commands and totally ignoring yours, which is a continuous frustration. That’s no way to be working on a Mac.
Besides, you were actually quite fond of macOS Sierra.

2.Some of your apps require testing on macOS Sierra

If you occasionally test apps, it might get to the point where you will likely be tied to a specific operating system. And if most of those apps require macOS Sierra, you’ll have to downgrade. Another option would be to set up a dual boot Mac and have two operating systems running at the same time. However, for most Mac users, one OS is more than enough.

It might not even be about testing apps, but just about using apps. While many third-party apps have already transitioned to macOS High Sierra, we’re sure that some have slipped off the tracks. If this has happened to you, there’s no other way than to downgrade to a previous macOS version.

3. Many of your favorite apps are 32-bit

With the release of macOS High Sierra Apple has ditched the support of 32-bit architecture applications. And as of today, not all developers have managed to convert their programs to 64-bit. If some of your apps happen to be in 32-bit (you'll know this as they just wouldn't launch on High Sierra), it's reasonable to downgrade to regular Sierra.

Now you are ready to downgrade to macOS Sierra

Step 1: Clean up your Mac’s drive

We told you that the backup was an essential step and now you see why: we’re going to clean up your machine. That’s because compared to macOS High Sierra, the regular macOS Sierra requires more space on drive to operate, thus the disk cleaning. And again, a fresh drive is preferable if you’re about to reset an operating system.

For a quick disk cleanup you can use one of Mac cleaner apps out there. CleanMyMac is especially good for this cause, as it has built-in Large & Old Files search. Download the app (it’s free to try) and remove all useless files it finds on every drive, like system junk, old Mail attachments etc. Interestingly, CleanMyMac finds up to 74 GB of junk on an average Mac, which should give your macOS Sierra a lot of free space to breathe.

Step 2:Back up your Mac

This step should become a part of any Mac user’s ritual. Whether you use Apple’s own software – Time Machine – or chose to manually backup files on a Mac, you need to make sure your important documents are protected and risk-free. And while you should do this on a regular basis, it’s almost obligatory each time you reconfigure your Mac. Especially during installation procedures, such as downgrading to an older macOS version.

Step 3: Erase macOS High Sierra

Now, follow the process of re-installing the macOS Sierra version. This is a simple process, and all you have to do is follow the prompted instructions. In no time, you’ll complete the downgrade to macOS 10.12.

  1. Connect to Time Machine
  2. Restart your Mac in Recovery Mode: press Command + R while you reboot
  3. At the macOS Utiities screen press Disk Utility
  4. Click Continue and then select Startup Disk (where OS is located)
  5. Hit Erase. Choose a new disk name and select Mac OS Extended (Journaled) format

Step 4: Restore the backup on your Mac

Once you finished the installation process, use Time Machine or the external disk you manually did the Mac backup upon to restore all the important data you will need. If you’re restoring from Time Machine, you’ll again have to reboot, press Command+R and go to Disk Utility. Select the most recent back up and hit Continue.

How to go back to an even older macOS version

The downgrade process described above works for any macOS. If say, you’d want to downgrade from macOS High Sierra to El Capitan, you could easily do that by changing only Step 3. However, there’s another option if you want to get back to your latest macOS version. This is possible by using Time Machine. Here’s how:

  1. Restart your Mac while pressing Command + R
  2. Open Disk Utility and click on “Restore from a Time Machine Backup
  3. Choose the Time Machine backup disk you need and the disk you want to restore
  4. Click continue and follow the instructions when prompted

Of course, this procedure is only possible if you have used Time Machine (we strongly recommend you do, as it will save you a lot of sweat in the long run). Choosing to manually backup your Mac is also a good option, but it will rob you of many functionalities and benefits the Time Machine offers along the way.

If you need a bit more insight on the steps of reverting to a previous macOS, check outthis article:
Downgrade from macOS Sierra

Even if the operating system in case is different, the process remains the same.

Whatever option you choose, you ought to have a bit of patience. Your Mac will have a lot of thinking to do and the whole process requires some time. So, get yourself a snack and start following the steps above, just as you’d follow a cooking recipe, and you’ll handle your downgrade from macOS High Sierra successfully.

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When macOS Mojave was announced, Apple warned that it would be the last version of macOS that would support older 32-bit apps. Apple has been phasing out 32-bit apps for the last 10 years and is now ready to take the final step, even if Mac users may not be ready to lose access to older apps.


With the release of macOS Catalina, 32-bit app support is no longer available, which means many of your older apps will no longer work if they haven't been updated to 64-bit.

32-bit vs. 64-bit

32-bit apps date back to a time when there were 32-bit processors and 32-bit operating systems, but are now outdated. Apple has long since transitioned to 64-bit processors and macOS has been 64-bit since the launch of Snow Leopard in 2009.

Compared to 32-bit apps, 64-bit apps can take advantage of more memory and offer faster system performance. Apple technologies like Metal only work with 64-bit apps, and for Apple to ensure that Mac apps include all of the latest advancements and optimizations, support for 32-bit needs to end. In the simplest terms, 32-bit apps are inefficient.

32-bit apps can run on a 64-bit system as they've been doing for years, but Apple wants to get rid of outdated apps to make sure everything that runs on the Mac is properly optimized and isn't an unnecessary drain on system resources.

Previous Warnings

Apple started warning Mac users about plans to end support for 32-bit apps back with macOS High Sierra. In High Sierra, users started getting warnings about a 32-bit app's future incompatibility with macOS.

Sierra Update For Mac


A similar message was available in macOS Mojave, and if you opened up a 32-bit app while running Mojave, you saw an alert letting you know a specific app wouldn't work with future versions of macOS unless it was updated.

Alerts re-appeared every 30 days when launching an app, with Apple aiming to make sure customers would not be caught unaware when a 32-bit app stopped working in the future, so you should already know if one of your frequently used apps hasn't been upgraded to 64-bit.

Upon updating to ‌macOS Catalina‌, you'll be shown a list of 32-bit apps that no longer work on your system.

How to Check if an App is 32-Bit or 64-Bit in macOS Mojave

To determine whether an app is 64-bit or 32-bit and to see if there are 32-bit apps installed on your machine before upgrading to ‌macOS Catalina‌, follow these steps:

  1. Click the Apple symbol () in the menu bar on your Mac's desktop.
  2. Click on About This Mac.
  3. Choose 'System Report' at the bottom of the window.
  4. Scroll down to the Software list on the sidebar.
  5. Select Legacy Software.'

Anything in the list of Legacy Software applications is a 32-bit app and will not work when upgrading to ‌macOS Catalina‌.

If Legacy Software isn't an option in the sidebar, select the Applications option and then check the list of apps at the right. The column that's labeled 64-bit will show a 'No' listing for apps that are 32-bit.

How to Prepare to Update to ‌macOS Catalina‌

The first step is to make sure there aren't already available updates for apps that you have on your system, which you can generally do by updating through the Mac App Store for ‌Mac App Store‌ apps.

Mac High Sierra Update

Apps outside of the ‌Mac App Store‌ use other update methods that can vary by app, but for many, you can click on the app's name in the menu bar and choose the 'Check for Updates' option. Some other apps have more hidden update methods, so if you do have a 32-bit app, make sure to Google how to update it to be sure there's not already new software available.

After ensuring you've updated everything you're able to update, you can contact developers and ask them to update their apps, but if that doesn't pan out, the only other solution is to start the search for an alternative app if you're committed to upgrading to ‌macOS Catalina‌ or have already done so.

32-Bit App Warnings When Installing Catalina

When upgrading to ‌macOS Catalina‌, the installer will show a list of recently used apps that are 32-bit so you know what to expect before installing.


After viewing this list, you can choose to either cancel or continue with the installation.

‌macOS Catalina‌ also shows a stop symbol over the icon of 32-bit apps in the Finder, so you know that the app isn't going to open.

Aperture

With the release of ‌macOS Catalina‌, Aperture is going to stop working. Apple warned Aperture users in April 2019 that the software won't run in future versions of macOS, starting with ‌macOS Catalina‌.

Mac High Sierra Update List Of Apps

If you're an Aperture user, you'll have to transition to alternate photo editing and management software, such as Adobe's Lightroom. Aperture is not 32-bit, but Apple is phasing it out all the same.

Affected Media Formats

Certain media files that use older formats and codecs are also not compatible with macOS after macOS Mojave due to the 64-bit transition, and you will need to convert some iMovie and Final Cut Pro X libraries. Incompatible media files were created using codecs that rely on QuickTime 7, and while macOS Mojave has QuickTime 7 frameworks, future versions of macOS will not.

Apple has a full list of media formats that are going to be affected by the transition available in a support document.

Continuing to Use 32-Bit Apps

In macOS Mojave and earlier versions of macOS like High Sierra, you can continue to use your 32-bit apps. If you have a 32-bit app that you absolutely depend on, you're going to want to think twice before upgrading to ‌macOS Catalina‌.

Guide Feedback

Have questions about the end of support for 32-bit apps or want to offer feedback on this guide? Send us an email here.