SOLVED Upgrade to Catalina?

[mikemac]

Desktop iMac (21.5 inch, Late 2013), Intel Core i5, SATA Disk 1TB, Running on OS Mojave (10.14.6).
For quite some time Software Update shows to upgrade to Catalina (10.15.7).
My question is, are there any advantages to upgrade? will there be no operating complications and glitches? Note some of my files go back to 2006.
Strangely, when I click on More info... I'm taken to https://www.apple.com/macos/monterey/ which is not compatible with my hardware.

 

[TonyAguila]

Desktop iMac (21.5 inch, Late 2013), Intel Core i5, SATA Disk 1TB, Running on OS Mojave (10.14.6).
For quite some time Software Update shows to upgrade to Catalina (10.15.7).
My question is, are there any advantages to upgrade? will there be no operating complications and glitches? Note some of my files go back to 2006.
Strangely, when I click on More info... I'm taken to https://www.apple.com/macos/monterey/ which is not compatible with my hardware.

Mojave was the last version of macOS to support 32-bit apps. If there are 32-bit apps installed on your Mac that you still use and rely on, you will need to retain macOS Mojave. As an alternative, you can install macOS Catalina on an external drive while retaining your original Mojave system, or vice versa (Catalina on internal, Mojave on external).

You Mac’s model identifier is iMac14,1, I believe, and is indeed capable of running macOS 10.15.7. Should you elect to get an external SSD drive, and assuming your iMac has a fusion or hard drive, I suggest installing the version you plan to run more often from the SSD. Such a setup is not unusual. My 2018 intel Mac mini still has Mojave installed, along with Catalina, Big Sur, Monterey, as well as Ventura.

 

[mikemac]

Dear TonyA. Thank you for the info.
I will go ahead and install Catalina on an external SSD whilst retaining Mojave on the internal HDD.
Would you please give me directions:
(a) What size SSD should I buy
(b) How to install Catalina on SSD
(c) How will I choose boot up with SSD or HDD
(d) I'm already using an external drive connected toTime Machine for backups. Will it continue to backup both from HDD and SSD

 

[TonyAguila]

Dear TonyA. Thank you for the info.
I will go ahead and install Catalina on an external SSD whilst retaining Mojave on the internal HDD.
Would you please give me directions:
(a) What size SSD should I buy
(b) How to install Catalina on SSD
(c) How will I choose boot up with SSD or HDD
(d) I'm already using an external drive connected toTime Machine for backups. Will it continue to backup both from HDD and SSD

Let’s see…

(a) I would recommend 1 or 2 terabytes, no smaller, especially considering how SSD prices have become more affordable. Since your iMac does not have USB-C, and is probably on USB 3.0, I don’t think you will be able to connect the newer portable SSDs like the Samsung T7 or SanDisk Extreme, which are fitted with NVMe SSDs requiring USB3.2 Get 2. Look for ones with the SATA interface, maybe a Samsung 860 or 870 EVO. You will need a USB-A to SATA adapter. I have a Sabrent USB 3.1 to SATA adapter cable which will probably run about $15. It will not be as fast as Thunderbolt NVMe SSDs, but still a screamer compared to a hard drive (which, by the way, the Sabrent can also connect to).

(b) You can usually download macOS installers from the app store. Just search for “macOS [version]” but I just tried it and Catalina does not show up. Maybe it has to do with my hardware, so try searching for “macos catalina” and it might connect you to the download (aka “get”) page. Download it and as soon as it finishes the installer will launch. It will download it your Applications folder. You must first quit the installer so you can make a copy to another location. You will use this when you have your new SSD formatted and ready for the Catalina installation.

If somehow App Store will not provide the installer, you can find it here:

How to download and install macOS - Apple Support

Download and install current or previous versions of the Mac operating system on compatible Mac computers.

support.apple.com

(c) Once you have both macOS versions installed, you can reboot while holding down the option key. It will list the available startup drives to choose from. You can also use Startup Disk in System Preferences to select one. When formatting your new SSD, you need to choose APFS format, which I’m not sure if Mojave is able to. In any case, the Disk Utility app in Mojave was quite problematic, considering this was Apple’s first attempts with APFS. You must use Disk Utility in Recovery (boot up holding down command-R).

(d) Your iMac has four USB ports, right? You should be able to connect your Time Machine drive(s) alongside the external SSD. Have fun!

 

[mikemac]

Hi TonyA, Thank you very much for the instructions.
One last question: Since I have a Thunderbolt port can I connect the SSD there?

 

[TonyAguila]

Hi TonyA, Thank you very much for the instructions.
One last question: Since I have a Thunderbolt port can I connect the SSD there?

Since your iMac has Thunderbolt 2, you will need a Thunderbolt 2 to USB-C cable. This might enable you to use the USB-C external SSDs like the Samsung T7 or the SanDisk Extreme which can make it easier to connect. I have never tried this configuration myself so I suggest looking it up or inquiring directly from the manufacturer (SanDisk or Samsung) if this is possible.