Can't connect to any Apple site or App Store due to lack of secure connection

If you upgraded the RAM for that model then it can install up to El Capitan, which you can download using http (instead of https) from Apple here: http://updates-http.cdn-apple.com/2019/cert/061-41424-20191024-218af9ec-cf50-4516-9011-228c78eda3d2/InstallMacOSX.dmg

Once you upgrade macOS to El Capitan, you can update the browser to something a bit better, like Firefox 78.9 ESR from here: http://ftp.mozilla.org/pub/firefox/releases/78.9.0esr/mac/en-US/Firefox%2078.9.0esr.dmg

But you will really need to install Chromium Legacy to have half-decent browsing, from here: https://github.com/blueboxd/chromium-legacy. My personal choice when I was playing around with this one was to use the downloader by wowfunhappy to install some extras like the updated ISRG X1 certificate but not the full download and install because it disables some native Chrome features. But again, personal choice.

randle32 wrote:

I'm setting up an old iMac running Snow Leopard. When I try to connect to any Apple site or the App Store I get a message saying "unable to establish secure connection". I've looked at a dozen different help articles, tried everything they suggest, but nothing changes. Any ideas?

The original protocols used for https security were found to be less secure than thought, and there was a move to replace them with more secure ones, in browsers, and on Web sites.

El Capitan first got the changes for the new form of security. There may have then been back ports of the security patch to Yosemite and Mavericks (not sure) provided that you applied ALL of the available patches. Snow Leopard is too old and never got a security update. Its version of Safari does not support the forms of security which many modern https sites require. I don't know if there are any other browsers for Safari that do, either.

As an aside: I've also downloaded two different OSX upgrades, Mountain Lion and Yosemite, which I did get from the Apple OS site using Chrome. I ran each one. Each one ran without any issues and both said "Update complete" when they finished. However, the machine is still showing Snow Leopard. I'm wondering if this is related.

If your Mac shows that it is running Snow Leopard, it sounds to me like one of two things happened:

• You downloaded the installers, but did not run them, or did not tell them to actually install the newer OS, or told them to install it somewhere else. Thus you are running Snow Leopard because you never actually updated.
• Those versions of the OS are incompatible with your Mac, so when the installers ran, they quit without installing the updates.

Which Mac do you have - model name and hardware release year / time of year? That will determine the maximum version of the OS that it is eligible to run.

I believe the .pkg inside of the mounted disk image is what you want to run. It might have put up a dialog asking you on which volume to install El Capitan, but if you selected the right volume, and it ran to completion, and told you that the installation was successful … and the Mac still ran Snow Leopard after rebooting … maybe those old installers are now broken.

There was once an App Store compatibility patch for Snow Leopard on the Apple site. The purpose of the patch was to ensure the future compatibility of Snow Leopard with the App Store. However, I believe that it predated all of the https security changes, and it is quite possible that even if you had the patch installed, you simply wouldn't be able to access the App Store.

Mac App Store Update for OS X Snow Leopard - Apple Support

This update, and the App Store, require Mac OS X 10.6.8. If you are still on Mac OS 10.6 – 10.6.7, you need to bring Snow Leopard up to 10.6.8, then apply the App Store patch, then cross your fingers and pray.

Mac OS X 10.6.8 Update Combo v1.1 - Apple Support

randle32 wrote:

I tried both of your App Store links (thank you very much), but neither worked. If I can just get the OSX upgrades to work it should be saveable, but I'm losing confidence.

Those are Support article links, not App Store links.

They are https links, so you probably will need to access them using a modern Mac or PC, put the updates onto a USB drive, and then transfer the drive containing the updates to the old Mac.

Even if you can get the updates to the old Mac, and successfully installed on it, there is no guarantee that this will be enough to let Snow Leopard access the App Store. More likely, you will have to enlist the aid of a modern Mac or PC to get the El Capitan installer .DMG, itself, to the old Mac. Unfortunately, if the installer no longer works on that machine, I'm not sure if there's much you can do about it.

I think it's too old macOS to establish secure connection with Apple Site and Mac App Store. You need to install at least High Sierra or later to establish secure connection with Apple Site and Mac App Store.

I want to know your iMac model more detail as well.

randle32 wrote:

I have the 20" iMac early 2008.

MacTracker shows that Mac as having

• A two-core Intel Core 2 Duo (E8135 or E8335) running at 2.4 or 2.66 GHz.
• A maximum of 4 GB (official) or 6 GB (actual) of RAM. I was surprised to find that Other World Computing still carries old DDR2 RAM that is compatible with your machine .
• A 250 GB – 750 GB mechanical hard drive connected to a 3 Gbps (SATA-II) interface. That interface would be fast enough for a mechanical hard drive, but could limit the speed of a SATA SSD if you decided to replace the original mechanical hard drive with a SATA SSD.
• An optical drive.
• A 20" screen with a resolution of 1680 x 1050 pixels.
• USB 2.0, FireWire 400, FireWire 800, and Mini-DVI (an old interface for a monitor with up to 1920x1200 pixels)
• Being able to upgrade as far as El Capitan, but no further

It might be time to consider retiring that old Mac and replacing it with a 24" M4 iMac or with a system based on a M4 or M4 Pro Mac mini.