Upgrade of late 2015 imac

The late-2015 iMac is listed as compatible with macOS 12 Monterey.

macOS Monterey is compatible with these computers - Apple Support

❗️ – IMPORTANT – If upgrading from 10.14 Mojave or earlier, your older 32-bit apps & drivers won’t work in macOS 10.15 Catalina or newer! They must also be updated or replaced.  Use the free utility Go64 app from St. Claire Software to check your current apps.

The preferred method of upgrading macOS is to use System Preferences > Software Update.  But there is an alternative method and that is to download the macOS installer from the App Store and run it manually.

To download the macOS upgrade installer from the App Store click > macOS 12 Monterey.

Once downloaded, double-click the “Install macOS Monterey” app now found in the Applications folder to begin the upgrade.

Please see > How to download and install macOS - Apple Support.

helpthehopeless wrote:

Sorry "may need"??? That is an inconclusive answer that I dont know what to do with...

If you have a friend or family member with some Mac experience, ask them for some hands on help.

If not, another option is to take the Mac to your local Apple Authorized Service Provider for help updating.

To find a local Service Provider, go to > Find Locations

You've come here for guidance and assistance, and that is being offered in friendly fashion. None here are volunteering their time to mess with you or send you off to shady websites via unreliable links. That behavior would not be tolerated by our Apple hosts.

The link I posted is exactly what I suggested, a link to a small app called Go64 that, when installed, will list for you exactly which apps already installed on your Mac are coded in 32-bits and therefore not compatible with macOS 10.15 or newer. Those apps will require updates or replacement if you upgrade your Mac to Catalina or newer.

You can, however, manually check your apps yourself. Press your option key and click your Apple menu  > System Information. Then click the Software heading in the side bar on the left and Applications heading below that. In the panel to the right you'll be presented with a list of the applications installed on your Mac. If you select an app there you'll find its details below, including whether its 32-bit or 64-bit under "Kind:". None of your 32-bit apps will work in macOS Catalina or newer. Scroll through that list to get the bit info for all of your apps.

helpthehopeless wrote:

Sorry "may need"??? That is an inconclusive answer that I dont know what to do with...

that is basically because it is not absolutely necessary to step up one macOS at a time. but when making that big a jump, such as Sierra directly to Monterey, it is sometimes recommended to step up one MacOS at a time. especially if you have the time to do so. or at least upgrade to Catalina first, and then Big Sur before Monterey because there were many big changes made within those prior macOSes.

Apple released two sets of 21.5" iMacs in Late 2015: Retina ones with 4K screens and quad-core CPUs; and non-Retina "price point" models with 1080p screens. Your Mac is the slowest variant of the price-point model – it has only a 1.6 GHz dual-core CPU as opposed to the 2.8 – 3.3 GHz quad-core CPUs in the higher-end price point and Retina models. Even so, if that iMac has a mechanical hard drive or a 1 TB Fusion Drive, that is going to be one of the biggest contributors to perceived slow performance; something you might want to address by adding a USB 3 SSD and making that SSD your startup drive.

Your iMac originally ran OS X 10.11 or 10.11.1 (El Capitan), so if it is running 10.12.16 (Sierra) now, you missed out on most of the macOS upgrades that Apple provided at the time that Apple provided them.

Note that Monterey is not one of the “most recent three” supported by vendors like Microsoft and Adobe, and also does not receive current versions of Safari. You may not be able to download Pages, Numbers, and Keynote if you have never downloaded them before, as current versions require Sonoma or better.

Monterey is enough to run current versions of

• The Firefox Web browser and other major third-party Web browsers (Brave, Opera, Microsoft Edge, and Google Chrome).
• The LibreOffice office suite
• The Affinity Studio graphics and page layout suite (free with registration, if you don't need features like AI)

D.I. Johnson wrote:

You can, however, manually check your apps yourself. Press your option key and click your Apple menu  > System Information. Then click the Software heading in the side bar on the left and Applications heading below that. In the panel to the right you'll be presented with a list of the applications installed on your Mac. If you select an app there you'll find its details below, including whether its 32-bit or 64-bit under "Kind:". None of your 32-bit apps will work in macOS Catalina or newer. Scroll through that list to get the bit info for all of your apps.

To add to this, clicking on that "Kind" header will sort apps by that field, conveniently grouping all of the 32-bit apps together for easier identification.

Upgrading to macOS Catalina or later should supply 64-bit replacements for most apps bundled with macOS – although I am not sure about the big ones (Pages, Numbers, Keynote, iMovie, GarageBand) downloaded these days via the App Store. Third-party 32-bit apps are a different story, and all of them will die …

iTunes will go away, replaced by separate apps (Music, TV, Podcasts, Books) and the ability to manage iPhones, iPads, and iPods using the Finder.

helpthehopeless wrote:

thx - but I do not have "Software" in my System Information I have tried to use finder: applications: under "KIND" i only have "Program/File" Never have used "Pages, Numbers, Keynote, iMovie, GarageBand" so I guess it will make no difference.... thx for your time

This is from a Mac running Sequoia … but I'm pretty sure that things were similar on my old Late 2009 iMac when it was running High Sierra. (It's been sidelined for a year or two due to hardware failure.)

The Software heading is way down below the Hardware and Network lists (which I have collapsed here).

A Late 2015 non-Retina iMac can run Monterey.

You're welcome.

You may need High Sierra and/or Catalina before getting for Monterey.

see > How to download and install macOS - Apple Support