Sequoia

2025-10-18

Apple announced macOS version 15, "Sequoia," on 10 Jun 2023.
Apple released macOS 15.0 on 16 Sep 2024.
Apple released macOS 15.0.1 on 09 Oct 2024, fixing a security hole.
Apple released macOS 15.1 on 28 Oct 2024, fixing bugs and introducing "Apple Intelligence" for M-series Macs.
Apple released macOS 15.1.1 on 19 Nov 2024, fixing 2 security bugs.
Apple released macOS 15.2 on 11 Dec 2024, fixing 64 security bugs and 22 other issues, and adding new "Apple Intelligence" features.
Apple released macOS 15.3 on 17 Jan 2025, fixing 60 security bugs and adding Genmoji, and adding new "Apple Intelligence" features.
Apple released macOS 15.3.1 on 10 Feb 2025, fixing security bugs.
Apple released macOS 15.3.2 on 11 Mar 2025, fixing an "extremely sophisticated" security bug.
Apple released macOS 15.4 on 02 Apr 2025, fixing 131 security bugs and 14 Safari bugs.
Apple released macOS 15.4.1 on 28 Apr 2025, fixing 2 security bugs.
Apple released macOS 15.5 on 12 May 2025, fixing 46 security bugs and adding 8 Safari security fixes, a new Passwords app, and more AI.
Apple released macOS 15.6 on 29 Jul 2025, fixing 81 security bugs and adding Safari security fixes.
Apple released macOS 15.6.1 on 20 Aug 2025, fixing a high priority seurity bug.
Apple released macOS 15.7.1 on 02 Oct 2025, fixing a seurity bug with malicious fonts.

This note describes how to update a computer from an older version of macOS to Sequoia.

The latest version of macOS is version 26.0, "Tahoe", relesed on 15 Sep 2025.

I installed Sequoia 15.3.1 on one computer, updating from Sonoma. Took less than an hour. (I did a full backup first.) About 6 progress bars. It went smoothly. After installing it asked about

After I installed Sequoia, I made sure "Apple AI" was disabled in  ► System Settings... ► Siri ► Apple intelligence. ‌Sequoia‌ offered Apple AI features for for Writing Tools, Siri, Focus, Notifications, Mail and Messages, Photos, and Safari. No thanks. I do not plan to use AI tools. They give bad answers, make stuff up, and plagiarize others' work. (I turn off "autocorrect" for spelling because it sometimes gives comically bad answers: AI is much worse.)

I installed Sequoia 15.3.2 on one computer on 14 Mar, updating from Sonoma 15.3.1. Took about 20 minutes, including the backup. Other Mac users had reported that Apple Intelligence was turned back on after the restart, but this did not happen on my computer.

I installed Sequoia 15.5 on one computer on 15 May. It was very quick, maybe 15 minutes. The update re-enabled automatic software updates; I turned it off again. (Also Mail has enabled a new dumb feature that "categorizes" your mail into Primary, Transactions, Promotions, Updates. I disabled it by viewing my Inbox and unchecking "Show Mail Categories" in the "View Options" menu at the top of the window.) I installed Sequoia 15.5 on another computer on 21 Mar, updating from Sonoma 15.3.1. Took about 20 minutes, including the backup.

I installed Sequoia 15.6.1. Took about 10 minutes. Things looked OK but MySQL was not running. See what I did to fix it..

Apple has already seeded a version 15.7 to developers.

Features of Sequoia

See new features. (I have no plan to use the features marked *.)

See Apple's site macOS Sequoia.

Should I Install Sequoia?

Yes. It has been very solid for me. There are a lot of security fixes.

What you Should Do Now to Get Ready for Sequoia

Who Can Update

Not everyone can use the new OS version.

Plan your install

When you decide to install Sequoia, do it carefully. You may find that there are issues that affect you: do your homework. Check MacInTouch to see if there are problems with macOS 15 that affect you.

Make sure you back up your entire disk before starting to install Sequoia. Preferably to more than one place.

Make a list of the hardware you depend on, and search the web to check that each device will work. Older printers and scanners can have issues.

Leave yourself enough time. Upgrading will tie up your computer for an hour or so. Your computer may be slow until it re-does the Spotlight index.

Particular issues before upgrading

Here is a partial list of minimum program versions needed for Sequoia. For other programs, check product websites.

ProgramMinimum VersionNotesFunction
Aquamacs Emacs3.6Text editing
Audacity3.42Music editing
Adobe PhotoshopCC Photoshop CC is $120/yr. See below. (ARM supported.) Graphics
Adobe IllustratorCC Illustrator CC is $240/yr. See below. (ARM supported.) Graphics
Apple XCode15 free with registration; also install Command Line Developer Tools in Terminal application development
Little Snitch6.1.1 A new version of Little Snitch is required for Sequoia. (Some Apple traffic such as Maps and ads doesn't show in Little Snitch. This sucks.) Security
Brother HL-4150CDN driver Brother does not support this printer, according to their website. Support stopped at 10.15.x Catalina. Apple no longer maintains https://support.apple.com/en-us/HT201465 . I have this printer and it is working OK on Sequoia using the CUPS driver. Printer driver
Brother HL-5450DN driver Brother does not support this printer, according to their website. See above. I have this printer and it is working OK on Sequoia using the CUPS driver. Printer driver
Homebrew4.3.21, same version I had for Sonoma. Replaces MacPorts. This is where I get Perl, ImageMagick, Go, and GraphViz. Unix applications
Microsoft Office2021 .. they are no longer updating the apps. was $129 Word processing, spreadsheet, etc
Onyx4.5.6 free System configuration
Super Duper3.9.1 You should change all your backup volumes to be APFS. Much faster and more reliable. backup
Brother P-Touch Editor5.3.13 Label printer driver
Banktivity8 now $60/yr. Personal finance
Inkscape1.3.2 seems to be fixed. SVG drawing

Adobe: Renting Instead of Buying

Adobe no longer sells regular application versions of Photoshop, Illustrator, and Acrobat. Instead they rent you a Creative Cloud subscription. Stop paying, the apps stop working. They tell you that one advantage is that you'll get bug fixes and new features whenever they decide to release them. (There are a lot of tricky deals, initial teasers, different bundles. You could pay $20/app/mo or $600/yr for all CC apps. Adobe also sells Photoshop Elements 2020 and Premiere Elements 2020 as non-cloud applications for $100 each one-time, or both for $150.)

There are alternatives to Adobe products. I am using Affinity Photo and Affinity Designer. They are one-time-purchase instead of rent.

Affinity has been sold to Canva. Canva's other products are sold by subscription instead of one-time purchase. Ruh-roh.

I want a replacement for Adobe Acrobat: PDFPen ($80) might work. Has to be scritptable.

Microsoft: Renting Instead of Buying

Microsoft wants to rent you "Office 365" for $70/yr, $100/yr for up to 6 people. You can still buy a "forever" Home version of Office 2024 for about $141, providing Word, Excel, PowerPoint and Outlook.

There are free alternatives to Microsoft products. LibreOffice 25.2 is one.

Quicken: Renting Instead of Buying

Same story with Quicken. I bought Banktivity and it seems to work.

Banktivity: Renting Instead of Buying

Banktivity has gone from a one-time purchase to a yearly sub. Grrr.

Installing Sequoia

I installed Sequoia on 03/04/2025.

  1. Clean up and update software before installing.
    • You can download the Sequoia Installer from  ► System Preferences... ► Software Update. It is free. This downloads a large file, the Sequoia Installer, to your disk. You can create a bootable installer volume on a USB key using these instructions. (But see the TidBits article "Previously Downloaded OS X Installers No Longer Work".) Apple's license terms say you can update all your computers with one purchase.
    • Get the applications on your computer ready for Sequoia: apply the latest fixes.
    • Delete junk files. Carefully.
    • Delete Safari, iTunes, and Firefox caches, so your backup will be faster.
    • Write down your settings for applications and system parameters, e.g. your desktop background and screensaver. Some Apple-provided screensaver pictures may not be available in the next version: make a safe copy of anything you will want after upgrading.
    • Empty the Trash.
    • Clean up damaged and duplicate fonts.
    • Have your software license keys handy in case you have to re-authorize products.

    For Programmers

    • If you use MySQL, back up your databases with mysqldump databasename > db.sql. Then stop MySQL.
    • If you are using a local Apache, save a copy of /etc/apache2/httpd.conf.
    • If you installed modules via CPAN, make a list of them.
    • Homebrew often does not need to be reinstalled on a macOS upgrade. If you are changing machine architectures, compilers, etc, then uninstall it and then reinstall Homebrew, and the programs it installs, after updating the OS. To list your ports do brew list > brewmods.txt in a Terminal window.

    Here is a little shell script I run to do the backups.

    	#!/bin/sh
	# PRE-UPGRADE
	# .. run before an OS upgrade
	# .. saves lists of things that may have to be repaired after upgrading
	#
	# dumps them into $HOME/Documents/preup so that they will be synced to iCloud
	if [ -d $HOME/Documents/preup ] ; then
	  cp /etc/apache2/httpd.conf $HOME/Documents/preup/saved.httpd.conf
	  perldoc perllocal | grep :: > $HOME/Documents/preup/cpan_modules.txt
	  brew list > brewmods.txt
	  mysqldump mydatabase > $HOME/Documents/preup/mysql_dump.sql
	  echo "Back up your hard drive"
	else
	  echo "$HOME/Documents/preup not found.. create it and rerun"
	fi
	#
  2. Backup and prepare.
    • BACK UP YOUR HARD DRIVE to an external disk. I used SuperDuper to clone my whole drive. Some cautious people make two backups.
    • If you are using an anti-virus product like Microsoft Defender ATP, disable it, or installation will fail. Some anti-malware programs see the utility that converts HFS to APFS as malware, and prevent it from running. Since most anti-virus software is tightly integrated with the operating system, you may have to install a Sequoia-specific version of your software after installing Sequoia anyway. Check with the maker of your software.
    • If you connect your Mac to the network using Wi-Fi, select  ► System Preferences... ► Network ► Wi-Fi and delete any Wi-Fi networks you don't want to use. (If you don't, your computer could connect to a very slow network during installation, which will slow down your install.)
  3. Install
    • If you use a wireless mouse or keyboard, put in fresh batteries.
    • Set screen saver to NEVER, and turn off Time Machine.
    • Dismount and unplug or power off external drives.
    • Restart your computer. (I've had problems where my computer hangs on shutdown. Restarting seems to fix it for a while. Don't want this trouble when installing a new OS.)
    • Run the Sequoia (macOS 15) installer. If you downloaded it, use that copy. Or you can just select  ► System Preferences... ► Software Update and install by clicking on the link.
      • The installer will run for about half an hour, then reboot.
      • The "time remaining" will show wildly varying estimates as the installer proceeds.
      • Eventually you will be presented with a login screen; enter your password.
      • Then the system will display your desktop. All your files and applications should be there.
    • If Sequoia asks you if you want to "enable Desktop and Documents folder syncing to iCloud," you can say NO, and turn it on later. I say YES and use iCloud for this and it seems to be great.. I had to move files around to make it back up the right things. If you say YES, these folders will be backed up in iCloud and available on all devices, which you may not want. Saying YES may also enable "Optimize Storage" without asking, which will delete files from your computer's drive if it gets too full -- I do not enable this. Check  ► System Settings... ► Internet Accounts ► iCloud ► Optimize Mac Storage to make sure it is OFF. Adam Engst's TidBITS article on Optimized Storage is very helpful.
    • Once the install has completed, use  ► System Settings... ► General ► Software Update and  ► App Store... to make sure you have installed the latest versions of Apple software. This step may find additional OS and application updates (might take another hour).
    • Do a "smoke test" to verify that your computer is working OK: make sure the applications you depend on are still working. Try out the applications from Apple that were updated with the OS. If you have trouble, restore your backup and go back to the old OS version.
  4. Recover
    • Wait for Spotlight to finish indexing (may take several hours). Performance will suck till it finishes.
    • Turn on Time Machine and start your backup.
    • Restart the computer. Often this speeds things up.

Post Install Tasks

Once you are satisfied that your computer works acceptably, and you are going to stay on Sequoia, you can make some adjustments. Some folks have complained that installing an update changed their settings.

Customization

You will probably want to set up per-user customizations, such as your desktop background and screensaver. Visit every setting in  ► System Settings... and make sure it is what you want, and choose values for new settings. After each new OS generation this is something of an adventure; functions get renamed and moved around. See below.

Turning Off AI in Microsoft Products

My wife and I have old Microsoft Office installations of Word, Excel, and PowerPoint from 2023. Word is version 16.78. I did not want an "Internet version." I thought it was working until recently, when my wife tried to open a document from email, and got all kinds of offers from "help" using AI.

Here is what I did:

For me, doing this in Word also changed Excel and PowerPoint.

I have installed LibreOffice (free) and plan to use its tools going forward instead of Word/Excel/PowerPoint. This will require some learning and configuring of LibreOffice .. I will write it up.

Devices

All my attached devices from Sonoma worked fine on Sequoia without any change.

Sequoia Observations

Serious problem printing some PDF files in 15.6.1

Since upgrading to 15.6.1 on 20 Aug 2025, I have noticed a problem printing PDF files generated by some web sites. This version was created in August 2025. When I try to print a multi-page PDF, the print preview shows a teeny strip of all the pages of output down the page. In the print dialogue, "scale" is set to 4%. Trying to print fails. If I pick "scale to fill entire paper" it prints one page at full resolution. If I pick "scale 65%" it prints one page at full resolution. There seems to be no way to print the entire document on mulitple pages, the way it used to work. (As mentioned above, I am using the CUPS printer driver, because Brother no longer supports my HL-5450DN printer.)

New Feature in Photos: Enhanced Visual Search

Photos has a new setting: General > Enhanced Visual Search. It defaults to ON in Sequoia. This feature "allows Photos to privately match places in your photos with a global index maintained by Apple so you can search by almost any landmark or point of interest." This feature might cause some extra network traffic when you add photos. The Apple article About Enhanced Visual Search in Photos describes how Apple protects your privacy. Everything is done encrypted, and they don't know who is asking, and they don't remember the result on their servers. The feature is also in iOS 18's Photos App... I turned it OFF on the phone, to conserve bandwidth and battery.

Other New Features in Sequoia

(Starting with Sequoia 15.6 MacOS asks "Do you want to continue access" for screenshot and screen recording apps. These compe up weekly, on reboot, or when you log out and log back in. I don't use these so I have not seen the alert.)

Also see https://www.spyhunter.com/shm/fix-macos-sequoia-wifi-issues/

MySQL problems with 15.6.1, resolved

MySQL was installed by Homebrew, and Homebrew's instructions had said that MySQL 8.3 did not need to be updated for earlier versions of Sequoia. When I upgraded Sequoia to 15.6.1 in Sep 2025, OS installation went just fine, but MySQL stopped working. I had to upgrade MySQL to MySQL 8.4 and reinstall the libicuuc library.

Next Steps: Homebrew updates

Perl 5.38 is still running fine for me in Sequoia 15.6.1. Homebrew offers Perl 5.40, but there are no features I use or need and it requires extra steps, messing with environment vars, etc. I will wait until I need to install it.

I should get the latest versions of some tools.

New Sequoia Features I Am Not Using Yet

see above

Problems Using iPhone OS 18

see iPhone Photos

Planning for the Next Version of macOS

The next macOS version, macOS 26 "Tahoe," will be released on Monday, September 15. See https://www.apple.com/os/macos/ and https://tidbits.com/2025/06/09/major-changes-coming-in-%ef%a3%bfos-26/ . MacInTouch says "macOS 26 abandons all but a few 2019 and 2020 Intel Macs and will drop Intel Mac support entirely with macOS 27."

Tahoe's displays feature the "liquid glass" appearance, with a transparent menu bar and updated icons, and more AI, and more integration with iPhone.

The Register says: "Apple plans to shift its operating system naming to reflect the release year, moving from sequential numbers to year-based identifiers. Consequently, the upcoming releases will be labeled as iOS 26, macOS 26, watchOS 26, etc., streamlining the versioning across platforms. "

Keep a list of the software and devices you use and depend on, so you can check that they are supported.

Home | FAQ © 2010-2025, Tom Van Vleck updated 2025-10-18 12:42