Reinstalling Mac OS Catalina

Ah, I think I've cracked it. It had downloaded to the applications folder rather than Downloads where I expected it, and I had a USB disk I could erase and follow the instructions to make a boot disk. Installing Catalina now. Cross fingers for me!

Cheers!

I've tried all that. I can't access Catalina because the Safari in Mavericks is too old. The pages don't appear correctly. and there is no way to "download". I can't access through Apple Store either. I managed to download .dmg files for older versions in the hopes of working my way through upgrades but they keep coming up "File is damaged move to trash". I'm using this forum on my macbook which has Monterey, and again, I have downloaded a .dmg version of Catalina, put it on a usb disk to copy across but I get the same error message. Software update doesn't give me any options to upgrade Mac OS from Mavericks. Whichever way I turn something doesn't work.

It's a 2015 Macbook Air, but with Monterey. Clicking on the link from the help page goes to a Mac App store preview and then the only option is to view in the app store and press the "Get" button. However, when I do this it jumps into System Preferences Software Update then I get a message saying it's too old to install. There doesn't seem to be a download option.

I need to start again here it's all getting confused.

The Macbook, which is fine, I have tried to use to download a copy of Catalina, but it will only go through the install process via software update, which then of course tells me that it is to old to install on a Monterey Macbook, but I don't want that anyway - I'm just trying to get a copy for the iMac.

On the iMac, I can't access the link because I think the browser is so old in Mavericks that the pages don't appear properly so I can't see the link to click on it.

So I can access this page on the iMac:

https://support.apple.com/en-gb/HT211683

but when I scroll down to the Catalina link and click on it, I get the App Store preview. On the Macbook, I can see the link (attached), but on the iMac, the browser isn't working properly.

Thanks for the warning. I can't download Catalina using the option you gave because it goes to software update via app store and as my macbook is running Monterey, it won't do it.

It's the Macbook that has Monterey. The iMac has Mavericks. I can't seem to find Catalina on *that* mac when searching the app store.

It is, but the Safari as I explained doesn't show the page properly so I don't even have a working link to click on to get Sierra, Catalina or anything else. The page should appear as attached, but the button "View in Mac App Store" is not there. I've tried searching the App Store on the iMac for Catalina, but there's nothing that comes up for the OS. It's weird.