I want to download the Catalina Installer on my M1 mac to create a bootable installer for an older mac.

You cannot download the Catalina installer using normal methods on an M1 Mac since the M1 Mac shipped with Big Sur from the factory. Apple makes it extremely difficult to download macOS for other systems. You can try using DiskMakerX, but I have seen people report issues with using a third party app like this to make a bootable macOS USB installer.

A better option depending on the exact model of your older Mac is to try to boot the older Mac into Internet Recovery Mode using Command + Option + R to see if it will boot to the online macOS installer. Regardless of what OS it offers you, then you can upgrade to a later version if necessary since it should be easy to download the appropriate macOS installer that is compatible with that particular Mac. Apple has an article with instructions for creating a bootable macOS USB installer along with links to download various macOS installers from 10.11 to 10.15.

BrightPath wrote:

This was a very unhelpful post and seems like spam.

Just because what I suggested does not work doesn't mean it is Spam or incorrect. I provided you multiple options to achieve your goal. And complaining about my post like that will keep any other knowledgeable contributors from wanting to assist you since they would likely have posted something very similar and won't want to waste their time.

First, I noted that I have an M1 mac, so it is surely running Big Sur; therefore DiskMakerX won't run.

DiskMakerX should run, but it will need to have Rosetta installed if the developer has not made DiskMakerX a universal app. I provided you an option. I did not guarantee it would work and in fact I said others had mentioned having issues getting a Mac to boot with the USB installer made with the app even when using an Intel Mac.

Second, I want to create a bootable installer because the internet recovery mode is not working.

You didn't explain any details so I provided an option to reinstall macOS as long as the Mac doesn't have a hardware issue. If Internet Recovery Mode is not working, then at least one of the following is true:

• Older Mac does not support Internet Recovery Mode (Apple's information is a bit vague & confusing here)
• You have a network issue (try using Ethernet instead of WiFi for a faster more reliable connection to bypass possible WiFi issues which are hard to troubleshoot)
• Your older Mac has a hardware issue so a USB installer is unlikely to work either

Third, the links that you provided are broken. And four, of course I looked at the instructions for creating a bootable MacOS USB! The problem is I can install the Catalina Installer on an M1!!!! Thanks for wasting my time.

I just tested all three links in my other post and they all load the proper pages for me. You need to check your browser(s), computer settings, or local network or ISP issues. If you have any anti-virus apps, cleaning apps, or third party security software or browser extensions, then they could be interfering with the links.

The only way I know that you may possibly be able to create a Catalina USB installer on an M1 Mac is with DiskMakerX or some similar app, but DiskMakerX is the most common and popular app I know about. If Internet Recovery Mode is not possible on the old Mac for whatever reason, then you will need to find another Mac that is compatible with Catalina (or any other OS that the old Mac can run) in order to download and create a bootable Catalina (or other OS compatible with the older Mac) USB installer using the Apple article I linked previously.

Maybe you can get an Apple Store or an Apple Authorized Service Provider to assist you in creating a bootable macOS USB installer.