macOS Catalina‌ 10.15.6 Supplemental Update Released with Bug Fixes

Aug 12, 2020 - 7 Comments

MacOS Catalina update

‌Apple has released a Supplemental Update to MacOS Catalina 10.15.6 for Mac users running the Catalina release on their computers.

macOS Catalina‌ 10.15.6 Supplemental Update includes bug fixes specifically aimed at improving stability for virtualization apps (like VMWare, VirtualBox, and Parallels), and resolves an issue with new model iMac (2020 Retina 5k) where the screen appears dull and washed out after waking from sleep.

Additionally, Apple has released iOS 13.6.1 and iPadOS 13.6.1 update for iPhone, iPad, and iPod touch users.

Downloading & Installing MacOS Catalina 10.15.6 Supplemental Update

Always backup a Mac with Time Machine or your backup method of choice before installing updates to system software.

  1. Go to the Apple  menu, then select “System Preferences”
  2. Select the “Software Update” control panel
  3. Choose to update to MacOS Catalina 10.15.6 Supplemental Update

The Mac will require a restart to complete installation of the supplemental update.

MacOS Catalina 10.15.6 Supplemental Update Package Download

Users can also download a package installer to apply manually to Catalina if they’d prefer to go that route:

macOS Catalina‌ 10.15.6 supplemental update Release Notes

Release notes included with the supplemental update download are as follows:

macOS Catalina‌ 10.15.6 supplemental update includes bug fixes for your Mac.

– Fixes a stability issue that could occur when running virtualization apps
– Resolves an issue where an ‌iMac‌ (Retina 5K, 27-inch, 2020) may appear washed out after waking from sleep

The primary MacOS 10.15.6 release came out in July, along with security updates for Mojave and High Sierra.

MacOS Catalina is now basically in maintenance mode as Apple is working on the next major version of system software, macOS Big Sur (versioned as 11), which will debut later in the year.

Separately, Apple released iOS 13.6.1 and ipadOS 13.6.1 for iPhone, iPad, and iPod touch, which also includes bug fixes.


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Posted by: Paul Horowitz in Mac OS, News


» Comments RSS Feed

  1. John says:

    Question. Is there another beta in the works for Catalina… 10.15.7? or is Apple going to release Big Sur first?

    • Paul says:

      It’s possible that 10.15.7 could be released as a future bug fix update or something similar, or they could issue another several supplemental updates instead should the need arise.

      The next major release of macOS will be Big Sur (officially versioned as 11.0, though sometimes as 10.16).

  2. john s says:

    My iMac (21.5″, late 2013) was good up through OS 10.5.5. As soon as I loaded 10.15.6, the whole thing went sideways. The first, and most notable, was that, after login, it often took longer than 15 minutes to load my desktop! There were other untoward occurrences but, after about three hours of amazed observation and frustration, I threw in the towel and reloaded the last good backup of 10.15.5. This took a good long time, approximately 10 hours IIRC, but, was eventually accomplished. No problem since then. Believe I’ll run the Late 2013 string out as long as it’ll go and then look into a new unit. This “upgrade” is honestly the first problem we’ve had with this computing machine.

  3. JohnIL says:

    Catalina runs perfectly fine on recent Mac models, but older models like pre 2014 not so much. Apple has never been so concerned about older hardware compatibility anymore then Microsoft is about Windows 10 working on Windows 7 devices. In technology anything 4 or more years old is considered legacy hardware that may or may not be fully supported with todays operating systems. Consider it planned obsolescence.

  4. JP Miller says:

    I’m using a 2014 iMac and the update is taking longer than 14 hours at this point. I’ve restarted, reset PRAM, and plugged in an ethernet cable. I’ve noticed considerably slower speeds with Catalina. If this update doesn’t resolve then I’m downgrading to High Sierra or Mojave.

  5. Malin Ek says:

    Catalina is a catasteophy. Cannot use my printer or the office program and lots of other please help me downgrade to high sierra. Or mojave…


    Love the patches on this one!

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