Apple today released macOS Catalina 10.15.3, the third update to the macOS Catalina operating system that was released in October. macOS Catalina 10.15.3 comes over a month after the release of macOS Catalina 10.15.2.

‌‌macOS Catalina‌‌ 10.15.3 can be downloaded from the Mac App Store for free using the Update feature in the System Preferences app, and it is available to anyone who has a compatible Mac.

macos catalina wallpaper
macOS Catalina 10.15.3 has code in it that suggests a new "Pro Mode" is coming to Apple's Macs. Pro Mode appears to be an optional setting that overrides fan speed limits and energy saving restrictions to improve performance. The code says that apps "may run faster" but battery life could decrease and fan noise could increase.

It's not entirely clear if Pro Mode is coming to Macs in the 10.15.3 release, but the code is there so it is a possibility. According to Apple's release notes, the update includes Pro Display XDR optimizations and multi-stream video editing improvements.

The macOS Catalina 10.15.3 update improves the stability, reliability and security of your Mac, and is recommended for all users.
This update:
- Optimizes gamma handling of low gray levels on Pro Display XDR for SDR workflows when using macOS
- Improves multi-stream video editing performance for HEVC and H.264 encoded 4K video on the 16-inch MacBook Pro (2019)

For more on everything that's new in ‌macOS Catalina‌, make sure to check out our dedicated macOS Catalina roundup.

Related Forum: macOS Catalina

Top Rated Comments

sugargliderdude Avatar
sugargliderdude
70 months ago
i said i would install Catalina once its at 10.15.3 but still not sure if i should... hearing so many horror stories.
Score: 10 Votes (Like | Disagree)
jb-net Avatar
jb-net
70 months ago
Biggest question: Will it fix Mail's data loss bug? Or is Mail.app on Catalina still randomly deleting E-Mails?
Score: 8 Votes (Like | Disagree)
pavvel Avatar
pavvel
70 months ago

Fingers crossed for Notes syncing with iCloud again.
Never had a problem with notes syncing since the first version.
Score: 5 Votes (Like | Disagree)
VanNess Avatar
VanNess
70 months ago

I would switch the Apple Mail if it did one thing Outlook did. Separate days in my inbox. I have today, yesterday, last week and older in my main view in Outlook. Apple Mail is just here you go, sort it out.
You can set up smart mailboxes ('https://support.apple.com/guide/mail/use-smart-mailboxes-mlhlp1190/mac') for today, yesterday, last week, etc. Pretty easy to do and I have it set up that way with links copied to the favorites bar. Since they are smart mailboxes your inbox remains untouched. Since doing this I rarely access my inbox. No need.
Score: 5 Votes (Like | Disagree)
macintoshmac Avatar
macintoshmac
70 months ago

Biggest question: Will it fix Mail's data loss bug? Or is Mail.app on Catalina still randomly deleting E-Mails?
It was said to have been fixed in the third beta. If this build is the same or higher, the bug may be fixed. MR has stopped giving build numbers long back, so just wait for someone to provide you with a build number. I am downloading it, but did not bother to catch the build so can't tell you right now.
Score: 4 Votes (Like | Disagree)
Steve121178 Avatar
Steve121178
70 months ago

I just installed the update and the issue with the external monitor and the fans is still there, right now the fans are running at 3200 RPM and the machine is really hot just by browsing the web to get to this page.

I talked to Apple support (again) and now they want a video of the machine so they can hear the fans running, I can't believe that a company that just announced that made 92 billions in revenue in the last quarter can't replicate this issue on their offices. I'm starting to think that their priorities have changed
Not being funny, but you should know the Mac and macOS isn't a priority. The Mac has been severely neglected for many years and macOS gets a token annual update that doesn't really add very much and just further aligns the desktop OS with iOS in one way or another. There's been very little innovation and advancements with macOS.

The number of bugs and issues with Catalina is inexcusable, but do they really care? NO, they don't.

All the talent has been pulled from macOS over the years to work on iOS & it's variants as that is Apple's future. The Mac isn't.
Score: 4 Votes (Like | Disagree)
Read All Comments

Popular Stories

iPadOS 26 App Windowing

Apple Explains Why iPads Don't Just Run macOS

Friday June 13, 2025 7:46 am PDT by
iPadOS 26 allows iPads to function much more like Macs, with a new app windowing system, a swipe-down menu bar at the top of the screen, and more. However, Apple has stopped short of allowing iPads to run macOS, and it has now explained why. In an interview this week with Swiss tech journalist Rafael Zeier, Apple's software engineering chief Craig Federighi said that iPadOS 26's new Mac-like ...
Read Full Article • 222 comments
iphone 16 pro models 1

17 Reasons to Wait for the iPhone 17

Thursday June 12, 2025 8:58 am PDT 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 simultaneously, which is why we often get rumored features months ahead of launch. The iPhone 17 series is no different, and we already have a good idea of what to expect from Apple's 2025 smartphone lineup. If you skipped the iPhone...
Read Full Article • 69 comments
Logitech Logo Feature

Logitech Announces Two New Accessories for WWDC

Friday June 13, 2025 7:22 am PDT by
Alongside WWDC this week, Logitech announced notable new accessories for the iPad and Apple Vision Pro. The Logitech Muse is a spatially-tracked stylus developed for use with the Apple Vision Pro. Introduced during the WWDC 2025 keynote address, Muse is intended to support the next generation of spatial computing workflows enabled by visionOS 26. The device incorporates six degrees of...
Read Full Article • 23 comments
iOS 26 Screens

Here Are All the iOS 26 Features That Require iPhone 15 Pro or Newer

Thursday June 12, 2025 4:53 am PDT by
With iOS 26, Apple has introduced some major changes to the iPhone experience, headlined by the new Liquid Glass redesign that's available across all compatible devices. However, several of the update's features are exclusive to iPhone 15 Pro and iPhone 16 models, since they rely on Apple Intelligence. The following features are powered by on-device large language models and machine...
Read Full Article • 58 comments
CarPlay Liquid Glass Dark

Apple to Let iPhone Users Watch Videos on CarPlay Screen While Parked

Thursday June 12, 2025 6:16 am PDT by
Apple this week announced that iPhone users will soon be able to watch videos right on the CarPlay screen in supported vehicles. iPhone users will be able to wirelessly stream videos to the CarPlay screen using AirPlay, according to Apple. For safety reasons, video playback will only be available when the vehicle is parked, to prevent distracted driving. The connected iPhone will be able to...
Read Full Article • 70 comments
iOS 26 on Three iPhones

Hate iOS 26's Liquid Glass Design? Here's How to Tone It Down

Wednesday June 11, 2025 4:22 pm PDT by
iOS 26 features a whole new design material that Apple calls Liquid Glass, with a focus on transparency that lets the content on your display shine through the controls. If you're not a fan of the look, or are having trouble with readability, there is a step that you can take to make things more opaque without entirely losing out on the new look. Apple has multiple Accessibility options that ...
Read Full Article • 211 comments
Mac Studio Feature

Apple Begins Selling Refurbished Mac Studio With M4 Max and M3 Ultra Chips at a Discount

Thursday June 12, 2025 10:14 am PDT by
Apple today added Mac Studio models with M4 Max and M3 Ultra chips to its online certified refurbished store in the United States, Canada, Japan, Singapore, and many European countries, for the first time since they were released in March. As usual for refurbished Macs, prices are discounted by approximately 15% compared to the equivalent new models on Apple's online store. Note that Apple's ...
Read Full Article • 34 comments
iOS 26 Feature

Apple Seeds Revised iOS 26 Developer Beta to Fix Battery Issue

Friday June 13, 2025 10:15 am PDT by
Apple today provided developers with a revised version of the first iOS 26 beta for testing purposes. The update is only available for the iPhone 15 and iPhone 16 models, so if you're running iOS 26 on an iPhone 14 or earlier, you won't see the revised beta. Registered developers can download the new beta software through the Settings app on each device. The revised beta addresses an...
Read Full Article • 84 comments
maxresdefault

Everything Apple Announced at WWDC 2025 in 10 Minutes

Monday June 9, 2025 5:21 pm PDT by
At today's WWDC 2025 keynote event, Apple unveiled a new design that will inform the next decade of iOS, iPadOS, and macOS development, so needless to say, it was a busy day. Apple also unveiled a ton of new features for the iPhone, an overhauled Spotlight interface for the Mac, and a ton of updates that make the iPad more like a Mac than ever before. Subscribe to the MacRumors YouTube channel ...
Read Full Article • 166 comments