I've got an older iMac, maybe 2015-ish running Monterey OS that can no longer be upgraded. Is this a candidate for Linux, if so, what distribution? I'm no coder, so just something that works well is all I'm looking for to extend the life of the computer.

Maybe Rufus can help? I think that it will help with your request?
https://rufus.ie/en/

You can run most Linux distributions on Intel Macs, as well as some BSD distributions. You can also run MS Windows on an older non-ARM Mac. There are other, less well known, options as well. IIRC, you can even run OS/2 on an Intel Mac. Support for ARM-based (Apple's M chips) is a little thinner, but they can be found.

As for which version of Linux, this is highly personal, and probably depends more on what flavor of GUI one prefers than the underlying OS distribution. Different distributions use specific GUI frameworks as their default desktop. These are at least as varied as the Linux OS distributions themselves, and differ (mostly) in appearance, included applications, etc. KDE and Gnome are probably the most "established" options, but both are reputed to put a load on the hardware, requiring more CPU and RAM than others. Mate, Cinnamon, and Xfce are intended to be more lightweight. Personally, I use a desktop manager named "fluxbox" which is very simplistic, and easy to configure on most of my Linux systems and VMs. I find the "prettier" desktop managers a little too cutesy for my taste.

This link provides a decent overview of some of the most widely-used desktop managers. Of course, you can install any UI on any Linux distribution, it is just that each come with a default that alleviates one having to go through an addition install/configuration exercise.

Many new to Linux go with Ubuntu as their first install. I cannot fault this, it is an excellent distribution with great documentation and support. Debian is also very popular, if a little "old school." There are dozens of "which is the best Linux distribution" websites that provide decent recommendations and are worth perusing.

You don't necessarily have to commit before you try. Almost every Linux/BSD distribution can be found in a version that installs onto a thumb drive and allows you to test things out without having to do a full install onto your system disk (or even write to it). Part of my EDC are a couple of thumb drives I can use as needed on systems I find in the wild.

Linux is good, but I could not see its true utility when I tried it on a Mac.

I have found that the older Mac OS continue to work fine for a long time. You can perform the internet recovery for the latest is supported by the hardware.

You will discover that newer OS features like password will not be present. So, if you have modern iPad and apple watch these software items will not integrate with the older iMac. But, this is trivial if you are not wanting to spend on the newer iMac.

I think staying current on hardware is the best approach. I keep older items on duty but in places like the garage where all I need is YouTube videos to work on stuff.

Thanks all! I am having the HD replaced in that old iMac with an SSD as the older spinning drive died a few weeks ago. Guess I know what the "error code" was for now.

There are a few apps I use that are only available for Mac so I'm probably doing to have it setup for dual boot for the MacOS and probably Pop-OS since I have a System 76 Linux laptop to make it easy on myself. I'm not a coder, just want outside of Microsoft/Apple/Google control...FREEDOM.

Ubuntu is the most MacOS like Linux. it should have no problems installing and running.

quote:

Originally posted by FenderBender:
Ubuntu is the most MacOS like Linux. it should have no problems installing and running.

I'd give the nod to Deepin rather than Ubuntu, or even UbuntuDDE (Ubuntu with the Deepin GUI).

Of course, macOS is about 90% BSD under the GUI "hood," so pretty much any BSD or Linux could be adjusted to look and act like it. Not to mention that, if you really do need a genuine macOS install, you can run it in a VM.

WRT keeping up to date on hardware, that is far less of a requirement with FOSS OS's than proprietary ones. Many FOSS OS distributions are designed to work fine with older hardware, something that cannot be said for macOS or MS Windows. For example, the most recent FreeBSD release supports systems built around the Motorola/IBM Power PC CPU and the even older Sun Sparc CPUs. Got an old PowerBook? You can install a modern, secure OS on it if you want (it may be a little slow by current expectations).