What is the 'not optimized for your Mac' warning message?

Macs running the latest OS version now warn users that any 32-bit app they launch is not “optimized for your Mac” and needs to be upgraded.

Apple, Mac, OS X, macOS, High Sierra, 64-bit, 32-bit

Mac users running the recently released macOS 10.13.4 update may see a new alert message when they log in and launch apps this morning, as Apple begins keeping its WWDC promise to push developers to upgrade their apps to 64-bit.

What is this alert?

Starting around midnight local time April 11 and 12, Macs running the latest OS version begin offering up a warning message the first time their users launched a 32-bit application.

macos high sierra 32 bit app alert Apple

32-bit app alerts are coming to macOS 10.13.4.

The warning states that the app is not “optimized for your Mac” and lets you know that it needs to be updated by the developer to improve compatibility. The warning will appear only once — the first time you open the app. It will also include a link to an Apple Knowledgebase article that explains a little more about why it is there.

Why am I seeing this message?

There’s no immediate reason to worry. Apple warned us of its plans to let macOS High Sierra users know when we are using 32-bit apps at WWDC 2017, but it waited until now to begin doing so.

Apple already demands that all new apps submitted to the Mac App Store be 64-bit, and from June 1 will insist that any software updates submitted to existing apps should also be 64-bit.

The pressure has been there for some time.

The company has been engaged in the transition to 64-bit for over a decade. The first Mac to appear with a 64-bit chip inside was the G5 PowerMac. Since then, the company has managed to ensure both its mobile and its Mac platforms run on 64-bit chips.

Apple has previously said that macOS High Sierra will be the last version of the Mac operating system to run 32-bit apps "without compromise."

Does this mean my 32-bit apps won’t work?

Short answer: No. Nothing has changed. Apple is not going to switch off 32-bit app support on your Mac. Those apps will still work fine, and your data will be safe. Final transition dates — also known as when Apple will switch off 32-bit app support on Macs — have not yet been set, though you may find that in the future the experience of using 32-bit apps will become more compromised.

Will 32-bit apps work on the next OS version?

Yes, 32-bit apps will work on macOS 10.14, but do hassle your developers to update them.

You see, I’ve learned that while Apple hasn’t fully defined to what extent 32-bit apps will be compromised when running on the next OS, it seems likely their use won’t be quite as straightforward.

I will note that in previous OS transitions, users have had to download additional software resources to make things work. Apple will still support these older apps — though they will be unable to fully exploit powerful system features, such as the graphics acceleration of Metal, which is 64-bit only. The bottom line? Their days are numbered. But nothing is broken. Yet.

What should I do if I see this alert?

You can easily check which (if any) of your apps Apple plans to disable in the future by following these instructions. Alternatively, you may see the alert when launching one of your apps. In either case, you should contact the developer of the software to ask about their plans to upgrade the software to 64-bit.

Otherwise, you needn’t worry much right now. Nothing much else will change, at least not immediately — but if you rely on an app whose developer does not intend to release an updated 64-bit version, then you should take steps to identify an alternative solution before Apple abandons 32-bit support altogether.

What should developers do?

Developers with existing 32-bit apps that are in regular use should take a look at Apple’s developer portal to find an extensive selection of resources designed to help them move their software to 64-bit. They’ll also find lots of ideas on how to use the transition to support new and interesting features in their software based on the 64-bit capabilities of the Mac.

What Apple is saying

Apple basically wants all the apps you use and rely on to transition to 64-bit as soon as possible. In most cases, this has already happened — Microsoft Word, Pixelmator and others have already made the switch, but Apple has learned (through previous transitions) that flagging up any kind of migration in advance is the best way to give developers a chance to keep up to date — and to give users the chance to motivate them to do so.

Apple puts it a little more simply:

“To ensure that the apps you purchase are as advanced as the Mac you run them on, all future Mac software will eventually be required to be 64-bit.

“Now is a good time to check with the software developer to see if 64-bit versions of your favorite titles are available,” it warns.

It will be interesting to see just how profound 64-bit support across all Apple’s platforms turns out to be in terms of the combined future of those platforms.

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Copyright © 2018 IDG Communications, Inc.

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