Apple's latest version of macOS, 10.15 Catalina, looks a lot like earlier versions of the operating system, but is hugely different under the hood. The biggest change is that Apple has removed all the code that made it possible in earlier versions to run older 32-bit apps in Apple's 64-bit operating system. Apple warned us years ago that this change was coming and there is no doubt that a 64-bit operating system such as Catalina is more efficient than an operating system that executes both 32-bit and 64-bit code. Yet Catalina blocks apps for many users that they have been relying on for years. Here we show you how to run 32-bit apps on an operating system that is not designed for them.
Before you update to Catalina, see if you use 32-bit apps that you cannot do without. The easiest way to do this is by clicking the Apple icon in the upper left corner, then About this Mac and then System Report and scrolling down to Software / Applications. It takes a while for your Mac to collect information about your apps and then displays a list of all apps on your machine. Find the column with the heading "64-bit (Intel)" and click on the column header. A yes appears in all of your 64-bit apps in this column. All 32-bit apps show a No. You may be surprised how many 32-bit apps you have. Study this list and if you find the 32-bit apps you need, you'll need to find a 64-bit update or replacement ̵
The 32-bit apps that you find on your machines are usually of two types: older Mac apps that have been abandoned by their developers (or that developers are slow to update) and apps based on the Wine software project that Macs and Linux computers can run Windows software. ( Wine stands for "Wine Is Not Emulator," but basically emulates Windows functions so that Macs and Linux boxes can run some, but not all, Windows applications.)
to create a 32-bit app, Apple unofficially recommends that you have an old Mac to hand that runs a pre-Catalina version of the operating system, or that you partition your current Mac so that it can also run with an older macOS version start up as Catalina. Both methods work, but both seem awkward and time-consuming to me. However, there are better alternatives.
The simplest method is this (but keep in mind that it costs money): buy a copy of Parallels Desktop or VMware Fusion if you don't have one yet. These support programs are usually designed to run Windows on a Mac, but you can also use them to create a virtual machine that runs macOS in a window on your Mac desktop. Parallels is the easiest to use, but VMware Fusion is not far behind.
The steps are different depending on whether you are still using macOS Mojave or have already upgraded to Catalina. Let's start with the steps you need to take if you are still using Mojave. Each step corresponds to a screen in the slide show.
1. Start Parallels Desktop
Choose New … from the File menu to open the Installation Assistant panel. In the Free systems section, scroll to the right and click Install macOS 10.14.6 using the recovery partition. (It may show a different version number on your system.) If you have upgraded to Mojave from an earlier OS version, you may see options to install that earlier version. Choose which version makes you feel most comfortable.
2. Create a new virtual machine
The next page in the Assistant has the header macOS 10.14.6. Click the Install button. Parallels launches the macOS installation program and creates a new virtual machine. When it's done, you'll see a screen asking you which language to use to communicate with your virtual Mac. Select the desired language and continue.
3. Preparing the macOS Mojave installation
The macOS recovery environment is now opened in the virtual machine. (This is the screen that every Mac displays when you hold down Cmd-R during startup.) On the macOS Utilities menu, click Reinstall MacOS. The following screen will offer to install macOS Mojave. Click Continue. On the license agreement screen, click Accept, and then click the Accept button in the pop-up menu.
4. Install macOS Mojave on the virtual disk
Do not be afraid of the following screen, which offers to install Mojave on a hard disk named Macintosh HD. This is not the hard drive of your Mac, but a virtual hard drive in the virtual machine that Parallels created. Click on Macintosh HD and then click Continue. Now wait while Mojave installs itself on the virtual drive. This can take more than half an hour.
5. Setting up MacOS Mojave
The virtual Mojave displays the same installation screens that the Mac normally displays when you install an operating system.
6. Complete the installation of macOS Mojave
When the installation is complete, you will see the standard Mojave desktop. Choose Actions from the main menu of your Mac (not the main menu in the virtual machine) and then install Parallels Tools.
7. Installing Parallels Tools
Follow the prompts to install the Parallels Tools in your virtual Mojave machine and restart the virtual machine.
8. Transfer your 32-bit apps
Drag your 32-bit applications from your real Mac to the virtual Mojave system. Double-click it to execute it. If you are using Mojave and not an earlier version, you will see the well-known pop-up warning that your 32-bit is not optimized for macOS and needs to be updated. Ignore the warning.
9. Upgrade the operating system
Now you can upgrade to Catalina. When the upgrade is complete, start Parallels Desktop and your virtual Mojave machine. (In this screenshot, Mojave & # 39; runs at night, so it shows the nocturnal desktop image, but it is the same virtual machine that was shown in earlier screens. Here I have a 32-bit app that does not run in Catalina itself. 
10. Wrap It Up
Go to the Parallels main menu with a 32-bit app and choose View / Enter coherence. own window on your Mac desktop and a second main menu (the menu for the virtual Mac) appears below the main menu of your main macOS installation As you can see in this window, my Mac with Catalina is just a 32-bit app Runs in a window that looks like any other app window The virtual machine dock is visible at the bottom of the screen, but it's easy to disable it via the virtual machine's system preferences.  You can now explore the Parallels options for close control over your apps and the app Use system preferences in the virtual Moja ve to have one or more 32-bit apps start automatically when the virtual machine is started. (Go to the Users and Groups preference pane and then the Login Items tab.)
Another Catalina option
But what if you have already upgraded to Catalina, or if you have a new mac that only runs Catalina , and you cannot install Mojave in Parallels with your Mac's recovery partition. Everything is not lost. You must download the Mojave installer from the Mac App Store and use it to install Mojave in Parallels.
Now that Catalina has been released, Apple does not display an option to download Mojave from the App Store, but it is still on Apple's servers. If you search deeply on the Apple website, you can find the web address that opens the App Store page where you can download the Mojave installer. I performed the search so you don't have to. Simply go to this Mojave page and the App Store offers the Mojave installer for download. Or, if you prefer to download and install the previous operating system, go to the High Sierra page.
Select the cloud icon to download the installation program. Your Mac will ask if you really want to download it; confirm that you are doing this and wait until it is downloaded to your Applications folder. Don't execute it! Start Parallels Desktop instead, use the File / New … menu to open the Installation Assistant. Click the middle icon & # 39; Install Windows or other operating system from a DVD or image file & # 39 ;. The following screen may show the macOS Mojave installation program; If this is not the case, drag the installer to the window and follow the instructions to create and use a virtual Mojave machine, as in steps 4 to 10.
If you have VMware Fusion , you must use the same procedure regardless of whether you have updated to Catalina. Start Fusion, click on New … in the menu to open "Select the installation method". You will see an option to install & # 39; macOS from the recovery partition & # 39 ;. Do not be tempted to use it, because it will tell you that it could not find a recovery partition, even if you know very well that a recovery partition is present. I asked VMware about this bug and maybe it will be fixed in a future version.
So instead of using the recovery partition, you need to download a Mojave or High Sierra installer, as described above, and drag it to the Select the installer window. Follow the instructions to install a virtual machine. When the new virtual system starts up, use the Install Virtual Machine / VMware Tools menu to install the VMware Tools. After you restart the virtual machine, drag in your 32-bit apps and run them in the same way that you can run them in Parallels. VMware uses the name Unity for the same option that Parallels Coherence calls; it runs an app on a virtual machine in a way that looks like the program is running in a window of your main macOS installation.
You can also run wine-based apps
What if you use a Wine-based app to run a Windows game or app? In almost all cases, the wine-based app does not work in Catalina. The simplest solution is to install Windows in Parallels Desktop or VMware Fusion and run the app in Windows. This costs money – you have to pay for a copy of Windows – and can be slow and complicated, but it is currently the only solution. The most prominent wine-based software vendor, CodeWeavers, is planning to release a Catalina-compatible version, but the task is not easy and it is not clear when the new version will arrive.
There is one exception to the rule that wine-based apps are not running in Catalina: if, and only if, you use 64-bit Wine, and if and and only if, your Windows app is a 64-bit app if it is simple enough to run under Wine, Wine can run it in a window under Catalina. The most effective way I've found this is to use the brilliant Wineskin Winery app – an open source project by a programmer using the doh123 name – in the form of an unofficial update by a programmer named it Gcenx used. (The original Wineskin Winery will not run under Catalina.) If there is enough interest in this topic, we will post a manual here, but there are probably not enough 64-bit Windows apps that can be used under Wine to make it worthwhile worth. Interested readers can search for "Unofficial Wineskin Update" to get started, but be prepared to hit your head on the table a few times until you find out.
Apple has not made it easy to run 32-bit apps under Catalina, but it is still possible. If you have found other ways to make it happen, please let us know in the comments section below.