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

2024 iPhone Boxes Feature

Apple Adjusts Trade-In Values for iPhones, iPads, Macs, and More

Thursday November 6, 2025 11:12 am PST by
Apple today updated its trade-in values for select iPhone, iPad, Mac, and Apple Watch models. Trade-ins can be completed on Apple's website, or at an Apple Store. The charts below provide an overview of Apple's current and previous trade-in values in the U.S., according to its website. Maximum values for most devices either decreased or saw no change, but the iPad Air received a slight bump. ...
Finder Siri Feature

Apple's New Siri Will Be Powered By Google Gemini

Wednesday November 5, 2025 11:57 am PST by
The smarter, more capable version of Siri that Apple is developing will be powered by Google Gemini, reports Bloomberg. Apple will pay Google approximately $1 billion per year for a 1.2 trillion parameter artificial intelligence model that was developed by Google. For context, parameters are a measure of how a model understands and responds to queries. More parameters generally means more...
iOS 26

iOS 26.1 Available Now With These 8 New Features

Monday November 3, 2025 5:54 am PST by
Following more than a month of beta testing, Apple released iOS 26.1 on Monday, November 3. The update includes a handful of new features and changes, including the ability to adjust the look of Liquid Glass and more. Below, we outline iOS 26.1's key new features. Liquid Glass Toggle iOS 26.1 lets you choose your preferred look for Liquid Glass. In the Settings app, under Display...
Liquid Glass General Feature

Apple Shares Liquid Glass Design Gallery

Thursday November 6, 2025 2:45 pm PST by
Apple is promoting the new Liquid Glass design in iOS 26, showing off the ways that third-party developers are embracing the aesthetic in their apps. On its developer website, Apple is featuring a visual gallery that demonstrates how "teams of all sizes" are creating Liquid Glass experiences. The gallery features examples of Liquid Glass in apps for iPhone, iPad, Apple Watch, and Mac. Apple...
apple watch se 3 always on

Apple to Remove iPhone-Apple Watch Wi-Fi Sync in EU With iOS 26.2

Thursday November 6, 2025 4:37 am PST by
Apple in iOS 26.2 will disable automatic Wi-Fi network syncing between iPhone and Apple Watch in the European Union to comply with the bloc's regulations, suggests a new report. Normally, when an iPhone connects to a new Wi-Fi network, it automatically shares the network credentials with the paired Apple Watch. This allows the watch to connect to the same network independently – for...
airtag purple

Apple's Website Lists AirTag 4-Pack at Shockingly Low Price [Updated]

Friday November 7, 2025 6:40 am PST by
Apple's online store in the U.S. is suddenly offering a pack of four AirTags for just $29, which is the same price as a single AirTag. This is likely a pricing error, and it is unclear if orders will be fulfilled. Apple has not discounted the AirTag four-pack in any other countries that we checked. Delivery estimates are already pushing into late November to early December, suggesting...
ikea smart home devices

IKEA Debuts 21 HomeKit-Compatible Smart Bulbs, Sensors, and Controls

Thursday November 6, 2025 4:08 pm PST by
IKEA today announced the upcoming launch of 21 new Matter-compatible smart home products that will be able to interface with HomeKit and the Apple Home app. There are sensors, lights, and control options, all of which will be reasonably priced. Some of the products are new, while some are updates to existing lines that IKEA previously offered. There are a series of new smart bulbs that are...
Home Hub Command Center with Dome Base Feature

Apple's 2026 Smart Home Revamp: All the Rumors

Wednesday November 5, 2025 3:54 pm PST by
It's been over a decade since Apple's HomeKit smart home platform launched, and it is overdue for an update. HomeKit and the Home app can no longer keep up with AI-powered solutions from other companies like Google and Amazon, but that's set to change with a smart home revamp that Apple has planned for 2026. Home Hub Apple is working on a home hub or "command center" that will serve as a...

Top Rated Comments

eji Avatar
73 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
73 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
73 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
73 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
73 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
73 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)