Many people remember Mac OS X 10.6.8 fondly. Not just 10.6 Snow Leopard, but particularly its very mature 10.6.8 release, the final one in that series. It’s considered a stable and perfectly fine version. It’s not a problem—until they want to mitgrate to a newer computer with the same files, preferences, users, and other elements as their current one. That’s particularly true when they want to keep their system and essentially brain transplant it to the latest two updates, macOS Catalina and Big Sur, and find there’s no direct path.
Apple offers Migration Assistant both when setting up a Mac (whether new or erased) and as an app within macOS, particularly to migrate user accounts and applications. As a source, you can use a Time Machine backup, a disk image copy of your macOS startup volume (via a cloning app, for instance), or another Mac.
But Migration Assistant has its limits: in Catalina and Big Sur, you must migrate from a backup made from or a computer running Mac OS X 10.11 El Capitan or later. Attempts to copy from older installations lead to an error.
However, you’re not stuck. You have several alternatives you can try.
El Capitan Os To Catalina Upgrade
Upgrade past 10.6.8
Macbook Pro 13' 2015 with OS X Yosemite on board. I've been trying to install OS X El Capitan, but always get the following message: 'This copy of the Install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading.' By the way this is not a date time issue, date is correct on my computer. If your Mac isn't compatible with the latest macOS, you might still be able to upgrade to an earlier macOS, such as macOS Catalina, Mojave, High Sierra, Sierra, or El Capitan. 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.
It may seem like a pain, but if you have a computer that can be upgraded to 10.11 El Capitan or later, that’s your best bet. This list of models from One World Computing will help you figure out if your Mac can be upgraded that far. It covers years of Mac releases. (No Macs that can run Snow Leopard can be upgraded to Catalina or Big Sur, which would solve the problem, too.)
Apple has instructions on installing a terminal release of Mac OS X or macOS for its old computers.
Once upgraded to El Capitan or later, you can then run Migration Assistant to transfer data to Catalina or Big Sur.
If your computer’s last OS option isn’t El Capitan, read on.
Copy just the user directory
When spanning such a long gap between releases, you may not need applications or any settings files—you just want to transfer all your document, pictures, and other personal files. In that case, you can use these directions in a Mac 911 column from last year. While that article was written to help you overcome a Migration Assistant failure, it also works when Migration Assistant can’t.
Each of the techniques in that article lets you move the files you need over to a new Mac. The options vary by what your older system is capable of and the level of technical detail you want to cope with.
Install an older Mac OS on an external drive for migration
If the Mac you’re upgrading to (not from) is in the right range of vintages, you can do the following:
- Install Mac OS X 10.11 El Capitan on an external drive. (Download El Capitan from Apple’s site.) El Capitan seems to be the last release that can migrate files from Snow Leopard.
- Use the Startup Disk preference pane to select that external drive and restart.
- Use Migration Assistant during setup or after setting up on the external drive to transfer data from your Snow Leopard Mac.
- Use Startup Disk to restart with your newer Mac’s intended startup volume.
- Now run Migration Assistant pointing to the external drive.
If you don’t own a Mac that can install El Capitan, you might be able to borrow such a machine from someone and use the same external drive approach that won’t affect the startup drive of their system.
This Mac 911 article is in response to a question submitted by Macworld reader Balthasar.
Ask Mac 911
We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to mac911@macworld.comincluding screen captures as appropriate, and whether you want your full name used. Not every question will be answered, we don’t reply to email, and we cannot provide direct troubleshooting advice.
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.
Check compatibility
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.
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
Hackintosh Upgrade El Capitan To Catalina
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.