Unable to update my iMac from macOS Catalina to macOS Ventura

chrismartin752 wrote:

I used to use Skype and now have to migrate to Teams. That needs (at least) Ventura. Is it possible to upgrade macOS one version at a time?

A heads-up:

These days, Microsoft has a policy of only supporting the three most recent versions of macOS.

If Apple sticks to the same release schedule that they have for the last ten years, Sequoia's successor will come out some time in September, October, or November of this year. Ventura will fall out of the "most recent three," and it may be only a matter of time until you are forced to upgrade to Sonoma or better to keep using Teams.

Yes, you can selectively install any version of macOS your machine can run.

See this document: How to download and install macOS - Apple Support

If that Mac is currently starting up off a mechanical hard drive, or a 1 TB Fusion Drive, you may want to consider getting an external SSD, and making it your startup drive. Slow drives are one of the most common causes of poor performance in late-era 21.5" iMacs.

I should add that the 2019 iMac I set up for family runs 15.5 Sequoia just fine today. It has been incrementally upgraded along the way from Catalina that it came with. There have been no "deal breakers" as far as performance goes, but of course there has been an occasional need to update a miscellaneous app here and there.

My point being that your iMac should do just fine with Sequoia.

chrismartin752 wrote:

I am running Catalina on my iMac (Retina 4K, 21.5, 2019). I need to upgrade to (at least) Ventura. I select Ventura on the AppStore, press "get" and the "Looking for Update" window opens and nothing else happens. I left it all night and the screen was unchanged in the morning.

I find it best and easiest to keep the Mac updated as near as possible to the latest, most current release of macOS.

In your case, Sequoia is the latest OS the 2019 iMac can run, and 15.5 is the current release.

Others have posted that you are likely to encounter issues with some of your Catalina-era apps, which is true. Now that you are trying to play catch up to five major OS revisions, you have potentially many more deferred issues than if you had kept the OS and your apps updated in a more timely manner. If you update/upgrade as the OS is revised, it is much easier to tackle any app issues one-at-a-time, rather than many-at-once when playing catch up, which can be very frustrating.

If avoiding any "gotchas" of new OS releases is your big concern, just wait a few weeks after an OS revision is released before you install it. Take that time to visit these forums and see what, if any, issues users might be having. Don't wait years to update/upgrade your Mac.

Were I in your position today, I'd focus on upgrading to Sequoia 15.5, probably in one fell swoop. Then I'd update any apps that complained. This would let me get the greatest remaining productive lifespan from the iMac with what is likely to be the last macOS version it will support. I did this with a Mac mini 2018 with no real issues.

And I agree with Servant of Cats' suggestion to use an external SSD as a startup drive to get the best performance from that iMac 2019. I once set up that same Mac for a family member and the difference was night and day.

Install macOS on an external storage device and use it as a startup disk - Apple Support

Use an external SSD as your startup disk … - Apple Community

That machine is technically capable of running macOS Sequoia.

Given that you are 5 major versions behind the current version, you're undoubtedly going to run into some "issues", especially with software compatibility with existing applications you may have.

As someone who ran Sonoma on a 2019 iMac for a short period of time, I can also almost guarantee that you're not going to be overjoyed with the performance...

What is prompting the need to update, other than the fact that Catalina is no longer supported?