macOS Sequoia 15.6 update brings security improvements and bug fixes

AppleInsider

Apple has released a further update to macOS Sequoia, with no specific new features but still overall improvements.

Apple has released macOS Sequoia 18.6

With macOS Tahoe little more than two months away from becoming the official, current release, Apple is no longer adding features to its predecessor, macOS Sequoia. That's usually the case with all macOS releases at this time of year, but Apple had previously been rolling out improvements to Apple Intelligence over several of the last few updates.

In this case, Apple's own documentation broadly only says that the new macOS 15.6 release contains bug fixes and security updates. There is one specific update, though, which is a fix to a bug relating to updating Mac firmware.

Reportedly, there were previously an issue concerning Device Firmware Update (DFU) mode in some circumstances. Apple has not detailed the problem, but it had resulted in situations where neither the Finder nor Apple Configurator could restore some devices.

The new release has been through several rounds of beta testing since it was first released to developers in June 2025. Since then, the testing has been running in parallel with Apple's macOS Tahoe beta releases, which recently included the first public one.

It's not recommended to install any test software, but even now that this macOS Sequoia update has left the beta stage, users should still delay installing it. While it's important to move to the latest OS update, it's best to leave it a few days.

That's because while macOS 18.6 was stable during the beta test phase, once any software gets out into the hands of millions of users, there will be problems. Give everyone else time to find them, and then Apple time to fix them.

Then while this is likely to be the last macOS Sequoia update before Apple switches to macOS Tahoe, there will be further updates to come. There will be no new features in them, but users can expect that security updates added to macOS Tahoe will also come to keep macOS Sequoia up to date and secure.



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phobos7

Yay! Good news to use

daveyd

Awesome read, thanks for the info. Unfortunately, I stumbled across this form too late and was one of the ones that immediately updated and found issues. I updated from Sequoia 15.5 to Sequoia 15.6, and the update went smoothly at first but then froze halfway through for several hours and still currently is frozen. I wanted to avoid turning my computer off during the update, but it might be my only option left. I’m going to wait a little longer though before attempting that. I know it’s not an issue on my computer either because I checked compatibly, disk space, etc and all looked well before updating. So to anybody else reading, I definitely don’t advise updating yet. 

mike wuerthele

DaveyD said:

Awesome read, thanks for the info. Unfortunately, I stumbled across this form too late and was one of the ones that immediately updated and found issues. I updated from Sequoia 15.5 to Sequoia 15.6, and the update went smoothly at first but then froze halfway through for several hours and still currently is frozen. I wanted to avoid turning my computer off during the update, but it might be my only option left. I’m going to wait a little longer though before attempting that. I know it’s not an issue on my computer either because I checked compatibly, disk space, etc and all looked well before updating. So to anybody else reading, I definitely don’t advise updating yet. 

While I'm sure you're dealing with what you say you are, there are no indications of more-than-normal installation issues.

This update fixes an actively exploited attack vector. We recommend upgrading as soon as possible.

edited July 31

daveyd

Mike Wuerthele said:

DaveyD said:

Awesome read, thanks for the info. Unfortunately, I stumbled across this form too late and was one of the ones that immediately updated and found issues. I updated from Sequoia 15.5 to Sequoia 15.6, and the update went smoothly at first but then froze halfway through for several hours and still currently is frozen. I wanted to avoid turning my computer off during the update, but it might be my only option left. I’m going to wait a little longer though before attempting that. I know it’s not an issue on my computer either because I checked compatibly, disk space, etc and all looked well before updating. So to anybody else reading, I definitely don’t advise updating yet. 

While I'm sure you're dealing with what you say you are, there are no indications of more-than-normal installation issues.

This update fixes an actively exploited attack vector. We recommend upgrading as soon as possible.

With all due respect, you say,

“We recommend upgrading as soon as possible,” now, but in the initial read you said,

“…even now that this macOS Sequoia update has left the beta stage, users should still delay installing it. While it's important to move to the latest OS update, it's best to leave it a few days.,” so which is it? That’s what I was commenting on prior when I was agreeing with your first assessment that immediate update installations aren’t recommended….

mike wuerthele

DaveyD said:

Mike Wuerthele said:

DaveyD said:

Awesome read, thanks for the info. Unfortunately, I stumbled across this form too late and was one of the ones that immediately updated and found issues. I updated from Sequoia 15.5 to Sequoia 15.6, and the update went smoothly at first but then froze halfway through for several hours and still currently is frozen. I wanted to avoid turning my computer off during the update, but it might be my only option left. I’m going to wait a little longer though before attempting that. I know it’s not an issue on my computer either because I checked compatibly, disk space, etc and all looked well before updating. So to anybody else reading, I definitely don’t advise updating yet. 

While I'm sure you're dealing with what you say you are, there are no indications of more-than-normal installation issues.

This update fixes an actively exploited attack vector. We recommend upgrading as soon as possible.

With all due respect, you say,

“We recommend upgrading as soon as possible,” now, but in the initial read you said,

“…even now that this macOS Sequoia update has left the beta stage, users should still delay installing it. While it's important to move to the latest OS update, it's best to leave it a few days.,” so which is it? That’s what I was commenting on prior when I was agreeing with your first assessment that immediate update installations aren’t recommended….

It's been a few days. There isn't a huge set of problems. 

Mass installation issues are found in the first few hours.

edited July 31