Apple Releases macOS Catalina 10.15.4 Supplemental Update With FaceTime Bug Fix

Apple today released a supplemental update to macOS Catalina 10.15.4, two weeks after releasing the macOS Catalina 10.15.4 update with Screen Time Communication Limits and Real-Time Apple Music lyrics.

macos catalina wallpaper
The macOS Catalina 10.15.4 Supplemental Update can be downloaded from the Mac App Store for free using the Update feature in the System Preferences app.

The new software introduces a fix that caused Mac computers running macOS Catalina 10.15.4 to be unable to participate in FaceTime calls with devices running iOS 9.3.6 and earlier or OS X El Capitan 10.11.6 and earlier.

Apple says it also addresses an issue with Office 365 accounts, fixes a bug that could cause a USB-C port to become unresponsive, and addresses a problem that caused the 2020 MacBook Air to hang during Setup Assistant or when connecting or disconnecting a 4K or 5K display. Full release notes for the update are below:

macOS Catalina 10.15.4 supplemental update improves the stability and security of your Mac.

- Fixes an issue where Mac computers running macOS Catalina 10.15.4 could not participate in FaceTime calls with devices running iOS 9.3.6 and earlier or OS X El Capitan 10.11.6 and earlier
- Resolves an issue where you may repeatedly receive a password prompt for an Office 365 account
- Fixes an issue where MacBook Air (Retina, 13-inch, 2020) may hang in Setup Assistant or when disconnecting and reconnecting a 4K or 5K external display
- Resolves an issue where a USB-C port in your Mac may become unresponsive

macOS Catalina 10.15.4 could be one of the last updates to the macOS Catalina operating system as Apple transitions to working on macOS 10.16, which is unnamed as of yet.

Related Forum: macOS Catalina

Popular Stories

iOS 26

15 New Things Your iPhone Can Do in iOS 26.2

Friday December 5, 2025 9:40 am PST by
Apple is about to release iOS 26.2, the second major point update for iPhones since iOS 26 was rolled out in September, and there are at least 15 notable changes and improvements worth checking out. We've rounded them up below. Apple is expected to roll out iOS 26.2 to compatible devices sometime between December 8 and December 16. When the update drops, you can check Apple's servers for the ...
Intel Inside iPhone Feature

Apple's Return to Intel Rumored to Extend to iPhone

Friday December 5, 2025 10:08 am PST by
Intel is expected to begin supplying some Mac and iPad chips in a few years, and the latest rumor claims the partnership might extend to the iPhone. In a research note with investment firm GF Securities this week, obtained by MacRumors, analyst Jeff Pu said he and his colleagues "now expect" Intel to reach a supply deal with Apple for at least some non-pro iPhone chips starting in 2028....
Photos App Icon Liquid Glass

John Gruber Shares Scathing Commentary About Apple's Departing Software Design Chief

Thursday December 4, 2025 9:30 am PST by
In a statement shared with Bloomberg on Wednesday, Apple confirmed that its software design chief Alan Dye will be leaving. Apple said Dye will be succeeded by Stephen Lemay, who has been a software designer at the company since 1999. Meta CEO Mark Zuckerberg announced that Dye will lead a new creative studio within the company's AR/VR division Reality Labs. On his blog Daring Fireball,...
ive and altman

Jony Ive's OpenAI Device Barred From Using 'io' Name

Friday December 5, 2025 6:22 am PST by
A U.S. appeals court has upheld a temporary restraining order that prevents OpenAI and Jony Ive's new hardware venture from using the name "io" for products similar to those planned by AI audio startup iyO, Bloomberg Law reports. iyO sued OpenAI earlier this year after the latter announced its partnership with Ive's new firm, arguing that OpenAI's planned "io" branding was too close to its...
iOS 26

Apple Seeds iOS 26.2 and iPadOS 26.2 Release Candidates to Developers and Public Beta Testers

Wednesday December 3, 2025 10:33 am PST by
Apple today seeded the release candidate versions of upcoming iOS 26.2 and iPadOS 26.2 updates to developers and public beta testers, with the software coming two weeks after Apple seeded the third betas. The release candidates represent the final versions of iOS 26.2 and iPadOS 26.2 that will be provided to the public if no further bugs are found during this final week of testing....
iphone air camera

iPhone Air's Resale Value Has Dropped Dramatically, Data Shows

Thursday December 4, 2025 5:27 am PST by
The iPhone Air has recorded the steepest early resale value drop of any iPhone model in years, with new data showing that several configurations have lost almost 50% of their value within ten weeks of launch. According to a ten-week analysis published by SellCell, Apple's latest lineup is showing a pronounced split in resale performance between the iPhone 17 models and the iPhone Air....
iPhone 17 Pro Cosmic Orange

iPhone 17 Pro Lost a Camera Feature Pro Models Have Had Since 2020

Thursday December 4, 2025 5:18 am PST by
iPhone 17 Pro models, it turns out, can't take photos in Night mode when Portrait mode is selected in the Camera app – a capability that's been available on Apple's Pro devices since the iPhone 12 Pro in 2020. If you're an iPhone 17 Pro or iPhone 17 Pro Max owner, try it for yourself: Open the Camera app with Photo selected in the carousel, then cover the rear lenses with your hand to...
ios 18 to ios 26 upgrade

Apple Pushes iPhone Users Still on iOS 18 to Upgrade to iOS 26

Tuesday December 2, 2025 11:09 am PST by
Apple is encouraging iPhone users who are still running iOS 18 to upgrade to iOS 26 by making the iOS 26 software upgrade option more prominent. Since iOS 26 launched in September, it has been displayed as an optional upgrade at the bottom of the Software Update interface in the Settings app. iOS 18 has been the default operating system option, and users running iOS 18 have seen iOS 18...
maxresdefault

iPhone Fold: Launch, Pricing, and What to Expect From Apple's Foldable

Monday December 1, 2025 3:00 am PST by
Apple is expected to launch a new foldable iPhone next year, based on multiple rumors and credible sources. The long-awaited device has been rumored for years now, but signs increasingly suggest that 2026 could indeed be the year that Apple releases its first foldable device. Subscribe to the MacRumors YouTube channel for more videos. Below, we've collated an updated set of key details that ...
iPhone 17 Pro Cosmic Orange

10 Reasons to Wait for Next Year's iPhone 18 Pro

Monday December 1, 2025 2:40 am PST by
Apple's iPhone development roadmap runs several years into the future and the company is continually working with suppliers on several successive iPhone models at the same time, which is why we often get rumored features months ahead of launch. The iPhone 18 series is no different, and we already have a good idea of what to expect for the iPhone 18 Pro and iPhone 18 Pro Max. One thing worth...

Top Rated Comments

eji Avatar
74 months ago
I was notified of this update right after my machine kernel panicked for the third time this week. It's a regular occurrence since the .4 update.

Admittedly, I was doing some pretty intense word processing at the time, so I can see why macOS would flake out.
Score: 23 Votes (Like | Disagree)
5097842 Avatar
74 months ago
I really wish Apple would push out a supplemental update for the kernel panic issue. I haven’t had any issues with Catalina until 10.15.4, now regular kernel panics during sleep. This is on a clean install of 10.15.4 as I thought it would be stable by now.
Score: 14 Votes (Like | Disagree)
DesertNomad Avatar
74 months ago
They really need a two year cycle on major OS versions - Catalina is still broken in many ways and they will simply move on instead of fixing it. I have been using Macs since System 6.0.3 on a Mac IIcx in 1989 and the current OS cycle is a mess. I miss Steve Jobs every day.
Score: 14 Votes (Like | Disagree)
cericsmith Avatar
74 months ago
I'm shocked and frustrated that Apple doesn't address this in the 10.15.4 Supplemental Update... This has got to be impacting many professional users!

I jumped through huge hoops to reinstall with 10.15.3 today to fix the kernel-panic/lockup that strikes when accessing external storage (ThunderBay 6, SoftRaid XT). I was getting hard locks randomly when hitting disks, even if it wasn't the RAID-5 TB6 -- just moving files from the MBP 15" SSD to an external SSD, both APFS formatted.

It's been a HUGE pain... first I thought it was the RAID -- took days chasing that down, multiple wipe/restores/verification passes... then I saw the original bug report on MacRumors re: KP's with 10.15.4... I moved the TB6 to a Mac mini also running 10.15.4 to verify the problem was also striking there (without any MBP-related power/nap/sleep complications), and it was indeed...

Apple didn't have 10.15.3 available to grab via Terminal, either...

The good news is that (if you can "track down" a working 10.15.3 full installer), installing over either 10.15.4 OR 10.15.5b1 works fine. Both of my Macs are back and running w/o problem on the same set of discs... I've moved many TB's of data in the last 5 hours since I rolled it back with no issues.

I will not be applying this or any other Catalina updates until this issue has been confirmed to be fixed.
Score: 10 Votes (Like | Disagree)
loby Avatar
74 months ago

('https://www.macrumors.com/2020/04/08/apple-releases-macos-10-15-4-supplemental-update/')

Apple today released a supplemental update to macOS Catalina 10.15.4, two weeks after releasing the macOS Catalina 10.15.4 update ('https://www.macrumors.com/2020/03/24/apple-releases-macos-catalina-10-15-4/') with Screen Time Communication Limits and Real-Time Apple Music lyrics.



The macOS Catalina 10.15.4 Supplemental Update can be downloaded from the Mac App Store for free using the Update feature in the System Preferences app.

The new software introduces a fix that caused Mac computers running macOS Catalina 10.15.4 to be unable to participate in FaceTime calls with devices running iOS 9.3.6 and earlier or OS X El Capitan 10.11.6 and earlier.

Apple says it also addresses an issue with Office 365 accounts, fixes a bug that could cause a USB-C port to become unresponsive, and addresses a problem that caused the 2020 MacBook Air to hang during Setup Assistant or when connecting or disconnecting a 4K or 5K display. Full release notes for the update are below:macOS Catalina 10.15.4 could be one of the last updates to the macOS Catalina operating system as Apple transitions to working on macOS 10.16, which is unnamed as of yet.

Article Link: Apple Releases macOS Catalina 10.15.4 Supplemental Update With FaceTime Bug Fix ('https://www.macrumors.com/2020/04/08/apple-releases-macos-10-15-4-supplemental-update/')
I hope Apple makes the decision to just "camp" on the island for another year instead of going somewhere else so they can just get this OS stable instead of introducing 10.16. Social distancing on Catalina island might be good for the OS.. :)
Score: 6 Votes (Like | Disagree)
sw1tcher Avatar
74 months ago

I was notified of this update right after my machine kernel panicked for the third time this week. It's a regular occurrence since the .4 update.

Admittedly, I was doing some pretty intense word processing at the time, so I can see why macOS would flake out.
I was writing a paper on the Mac and it was like beep beep beep beep beep and then like half my paper was gone. And I was like "Huh?" It devoured my paper. It was a really good paper. And then I had to write it again and I had to do it fast so it wasn't as good. It's kind of... a bummer.
Score: 5 Votes (Like | Disagree)