MacOS Catalina 10.15.3 Update Released & Security Updates for Mojave & High Sierra

Jan 28, 2020 - 27 Comments

macOS Catalina 10.15.3

Apple has released macOS Catalina 10.15.3, which includes bug fixes and security updates to the Mac Catalina operating system.

Separately, Mac users running Mojave or High Sierra will find new Security Updates available for those respective operating systems.

Additionally, iOS 13.3.1 and iPadOS 13.3.1 were released as updates, along with watchOS 6.1.2 for Apple Watch, and tvOS 13.3.1 for Apple TV.

How to Download & Install MacOS Catalina 10.15.3 Update

Be sure to backup the Mac with Time Machine before installing any system software update.

  1. Go to the Apple  menu and choose “System Preferences”
  2. Select the “Software Update” preference panel
  3. Choose to update to macOS 10.15.3 Catalina when it is shown as available for install
  4. MacOS Catalina 10.15.3 update

MacOS Catalina system software updates require a notable amount of free storage space available, and the computer must reboot to complete installation.

Recall that MacOS Catalina 10.15.3 updates are only available on a Mac that is already actively running MacOS Catalina.

For Macs running prior system software versions like macOS Mojave 10.14.6 or MacOS High Sierra 10.13.6, there will be Security Updates and Safari updates available to download instead through the system Software Update section of MacOS.

MacOS Security Update for Mojave

The availability of security updates for older MacOS releases is particularly useful to know if a Mac is ignoring MacOS Catalina software update for compatibility or any other reasons.

Download Links for MacOS Catalina 10.15.3 & Security Updates 2020-001 for Mojave & High Sierra

Another possibility is to install MacOS Catalina 10.15.3 (or the security updates) with a combo update or package update files. Using combo updates for MacOS is easy is much like installing a standard app package on the Mac and is fairly easy, nonetheless you’ll still want to backup before doing so.

MacOS Catalina 10.15.3 Release Notes

Release notes accompanying Catalina 10.15.3 are fairly brief, but presumably there are other bug fixes and enhancements included in the release.

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)

The release notes accompanying the security updates for Mojave and High Sierra are even simpler.


Related articles:

Posted by: Paul Horowitz in Mac OS, News


» Comments RSS Feed

  1. Steve says:

    This has bricked my A1398 EMC 2745 macbookpro.
    Now what?
    Not impressed Apple.

  2. Larry says:

    The 10.14.6 update essentially bricked my Mac Pro. The security accessibility/full disc access cleared everything out and nothing could be added, and then started locking up trying to launch apps.

  3. John says:

    Safari is a mess on 10.15.3… At first I thought it was just the BBC website but now facebook and other sites…. slow to load/don’t load at all and beachball!
    Tested the same sites on Chrome… No problem!

    Sigh! It all started going horribly wrong after snow leopard when apple took the lovely editing tools and stuff out of Preview… WHY?

    I like the reference to Vista made above,,,,, but alas that was Lion!!!! and Mojave… well that was simplty a missing year… unusable on account of the icon caching issue… now gladly rectified…

  4. Daniel says:

    They should have called it macOS Vista!

    • JohnIL says:

      Mac OS Vista? I like it. I did try a clean install with Catalina 10.15.3 hoping this will at least alleviate some of the issues. It does appear to have helped a bit. I am generally of the opinion that both IOS and Mac OS new releases have been pushed out too early leaving Apple to scramble to fix issues. Is there not enough testers to properly report the bugs? It’s becoming familiar to what Microsoft has faced with the Insider program.

    • tch says:

      or just macOs Brick

  5. Brian says:

    Updated my 2019 MacBook this morning. At the moment it is a brick. Will not power on period, have been on with Apple Support and all the reset sms attempts etc etc and nothing!

    They broke my last MacBook with an update, even a complete erase and back to the old OS install and it still does funky crap. Really sick of this sub-par crap Apple for an expensive product!

  6. Lee says:

    Just installed it on a Mac mini 2018, it was on 10.15.2, now the mac has gone offline, cant even be pinged. Another trash “OS” from Apple. This appears to be another LOW Sierra

  7. Norman says:

    After 6 hours of black screen and no reboot I gave up. How long does this update need on a high sierra 10.13.6? – A week, a year or simply for ever?

  8. Daniel says:

    System still crashes regularly when my external LaCie drive is connected using Thunderbolt. Doesn’t crash when using USB.

    • Sam says:

      My 2016 15″ MBP crashes *consistently* each time I eject an external hard drive (for Time Machine backups as well as data transfers)

  9. arrrrniii says:

    Upgraded my macbook pro last night, no problems. And finder hasn’t crashed all day today – major improvement!

  10. Mihhail says:

    Downloaded last update. Not possible to intall – every time when pressin “install now”, askin to restart, after restart same thing no installation, and so on by circle

  11. JohnIL says:

    Pretty big update for Mac 3.4Gb download and about 20 minutes or so to update my 2019 MacBook Air. Fingers crossed its stable.

  12. Jim Coleman says:

    Really Weird! I hit the link on the Apple download page to download the 10.15.3 combo and in reality the 10.15.2 combo is what actually downloaded.

    Also, the Apple support page is really brief on what this version corrects.

    I can only hope it corrects the glitches I have in “contacts” under Catalina.

    • Jim Coleman says:

      Just checked the Apple support page showing MacOS downloads and there are two (2) 10.15.3 Combo download links shown.

      Which one is the correct one?

  13. Barrie Stephenson says:

    No update available for my MBP 13” 2016 in the UK.
    Has it been pulled or is it on a phased roll out?

  14. Daniel says:

    Moving icons on the Desktop is now broken. Trying to move an icon to the first 2 columns from the right and below the 3rd row of the Desktop will always move the icon to the top of the screen when “Sort by> Snap to Grid” is selected.

  15. Peter says:

    When clicking the Combo update it brings you to what appears to be the correct webpage from Apple.
    But the download link on Apple’s website is for 10.15.2.

  16. Willy says:

    Looks like the download link for the 10.15.3 combo update points to the 10.15.2 update.

  17. Toodles says:

    The security release notes for these updates have some remote code execution vulnerabilities and so I would say it is important for Mac users to update to these versions of security update or Catalina if they are eligible.

    You can see details on the Apple website here

  18. Mate says:

    No eGPU fix for the Mac Mini 2018? Disappointing.

    There’s a long-running thread dedicated to the issue in case Apple engineers are reading this:

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