Unable to sign into my Apple account and access App Store due to age of my OS

How to download and install macOS - Apple Support

• Using a modern Mac or PC, download the .DMG file containing the Sierra installer, and put it onto a USB drive (portable drive or flash drive). This will not create a bootable drive, just a data drive containing a .DMG file. If you are preparing the drive on a Mac, do not format it using APFS. APFS wasn't around in Mountain Lion's day.
• Transfer the USB drive to the old Mac.
• Copy the .DMG file containing the Sierra installer to the old Mac, and eject the USB drive.
• Mount the disk image by double-clicking on (opening) the .DMG file.
• Run the installer inside to upgrade to macOS 10.12 (Sierra)
• Once you are on Sierra, its version of Safari and the App Store should work well enough that you can use the old Mac to access the above-linked Apple Support article, and to use an App Store link to get High Sierra or Mojave or Catalina.

You may want to make bootable clone backups of your Mac (using Carbon Copy Cloner or SuperDuper!) at each of the major steps. E.g., make a bootable clone backup of Mountain Lion before starting. Then, if the Sierra upgrade succeeds, make a bootable clone backup of it.

The idea would be that if something goes wrong, you don't necessarily want to be forced to rely on Internet-based Recovery. I believe that your Mac is new enough that it has that, but I'm not sure how reliably it works for such old Macs these days, and it's often better safe to be sorry.

Catalina 10.15 is the last macOS version that a 2012 iMac can run and it is to out-dated to use Chrome and most of the more recent App Store app's.

FWIW you maybe able to update it from 10.8.5 to Catalina 10.15, if you have access to a slightly newer Mac that can access the Mac App Store and create a bootable Catalina installer. see > How to download and install macOS - Apple Support

As an alternative… Borrow another less-old Mac if you can, download macOS 10.15 Catalina there, build a bootable installer there, and transfer the installer and boot and wipe your new old Mac, and install macOS 10.15.

• https://apps.apple.com/us/app/macos-catalina/id1466841314?mt=12
• Create a bootable installer for macOS - Apple Support

One of the fairly common issues with iMac purchases tends to be hardware under-configuration when originally purchased. The common low-end 8 GB memory and hard disk drive configuration is going to be very slow. Fusion drive — if you have that — will be less slow. That configuration can be worked around with booting and using an external SSD, at least to a degree.

Both iMac models from late 2012 are considered obsolete by Apple; both the 21.5” and the 27” model.

macOS 10.15 is five major versions back.

redhead2972 wrote:

• I have recently purchased a late 2012 iMac computer. Here are the specs.

processor: 2.7 GHz intel core i5

• software: OS X 10.8.5

I am unable to sign into my Apple account, log in to google chrome, access the App Store, etc.

Not much of a surprise there. Even if the Mac was prepared properly for resale, there was a big change in https security after people discovered that the original security protocol was not as secure as they thought.

I would guess that the version of Safari in Mountain Lion does not have the updates necessary to work with Web sites that insist on modern versions of https security. The App Store in Mountain Lion might easily suffer from a similar problem.

A Late 2012 iMac can run anything up to Catalina. Although Catalina itself is outdated, and is not enough to allow you to run current programs from the likes of Adobe and Microsoft, I would strongly urge you to update the OS on that old Mac. Your ultimate goal should be to

• Update it to High Sierra or Mojave – if you need to run old 32-bit applications that will break under Catalina.
• Update it to Catalina – if there isn't any reason to hold it back.

High Sierra or Mojave would be enough

• To run Firefox 115 ESR – which isn't getting new feature updates, and might not be getting security updates for much longer.

Catalina would be enough

• To run the current version of Firefox (but not the current version of Chrome, which requires Big Sur or later)
• To run current versions of the LibreOffice office suite
• To run the commercial Affinity V2 applications (Photo, Designer, Publisher)

Because Mountain Lion has such trouble accessing the Internet, you will need to do the upgrade in stages.

It seems like your Internet settings are not correct. Open up system settings. Navigate to "Network". On this page you should see your network interfaces. How are you connecting to the Internet? Wifi or Ethernet? If the stop light to the left of your interface is yellow or red it means it isn't configured correctly.

I currently have a 2012 iMac that connects just fine to the Internet.

Hope this helps.

Paul

redhead2972 wrote:

Or was this a mistake to purchase such an old computer…

If you want a desktop computer that can run current versions of macOS, you could take a look at

• The 24" M4 iMac – which has a nice, but small, 4.5K Retina screen.
• A Mac mini with a M4 Pro or M4 Max chip.

With the Mac mini, you add your own screen(s), monitor, and keyboard.

If the price and configuration was right, you could also consider a Certified Refurbished 24" M3 iMac, M2 Mac mini, or M2 Pro Mac mini. Apple usually only offers about 15% off the original list price – which may or may not be worth forgoing improvements you would get with a current product.

Certified Refurbished Products - Apple

If you do get a new or Certified Refurbished Mac, I would recommend getting one with at least 16 GB of RAM, and a 512 GB or larger internal SSD. You cannot upgrade RAM or the internal SSD after purchase.

Servant of Cats wrote:

...

• A Mac mini with a M4 Pro or M4 Max chip....

A correction: Mac mini features M4, and M4 Pro.

M4 Max is presently only available in MacBook Pro 2024.

Any Apple silicon will far outperform an Intel i5 from 2012.

MrHoffman wrote:

Servant of Cats wrote:

...

• A Mac mini with a M4 Pro or M4 Max chip....

A correction: Mac mini features M4, and M4 Pro.

Oops … don't know what I was thinking.

Thanks for the correction.

Paul Conaway wrote:

I currently have a 2012 iMac that connects just fine to the Internet.

I bet you are running something much newer than Mountain Lion on it, though.

Actually, I have Mojave running on it and primarily use it as a second monitor.