Archive for July 16, 2020

Thursday, July 16, 2020

macOS 10.15.6

Apple (also: MacRumors, Mr. Macintosh, Howard Oakley):

macOS Catalina 10.15.6 introduces local news in your Today feed in Apple News and improves the security and reliability of your Mac.

Unlike macOS 10.15.5, this does include a new version of Apple Mail. However, it’s not yet clear to me whether it fixes the data loss bug from macOS 10.15.0 where messages disappear when you move them. One user who had been frequently seeing the problem says that it stopped occurring some time ago—after the previous update but before this one—perhaps due to a change on Apple’s iCloud mail server. However, I would still like to see a fix in Mail itself because the bug also affected Gmail and other servers.

I have heard that some users are still seeing the bug from 10.15.0 where rules don’t move incoming messages to another mailbox automatically, only when manually applying the rules.

Update (2020-07-16): I received another report that iCloud messages no longer disappear. I also received a report that the bug with rules copying Gmail messages instead of moving them is fixed. I’m still not sure whether the data loss bug is fixed for non-iCloud servers.

Update (2020-07-20): One user reports Exchange messages disappearing when moved, although he’s not sure whether it’s due to a server problem or Apple Mail.

Update (2020-08-03): I’ve received several other reports of messages disappearing when moving them.


Update (2020-07-27): Mr. Macintosh:

The softwareupdate --ignore flag was changed to include some changes that we asked for!

Erik Schwiebert:

PSA: beware of MacOS [10.15.5] if you have any non-ASCII characters in your apps’ entitlement.plist files (even if they are HTML-encoded with &#...;). Late changes to the codesign tool error on them at signing time.

Juli Clover:

macOS Catalina 10.15.6 successfully fixes a frustrating bug that prevented some USB 2.0 accessories from working properly with 2020 MacBook Air and MacBook Pro models, according to MacRumors readers and users on Reddit.

Ole Begemann:

macOS 10.15.6 understands Big Sur’s APFS volume format. And apparently parallel installs of Catalina and Big Sur into the same APFS container are now supported (though I haven’t tried this).


Update (2020-07-29): Tanner Bennett:

You can only use the --ignore flag “as long as the Mac is enrolled in Apple School Manager, Apple Business Manager or a User Approved MDM”?


Update (2020-08-07): Howard Oakley:

My iMac Pro had clearly suffered a kernel panic as a result of a memory leak, which ran zone kalloc.48 out of memory, which it couldn’t recover. This may be unassociated with the bug that’s affecting virtualisation software, but makes me suspect that they result from the same memory leak. In which case, any Mac running 10.15.6 could be so affected.

I hope that Apple’s engineers are onto this case, and that we’ll soon see a Supplemental Update to 10.15.6.


My MBP kps and shuts down every three days. When I boot back up iStat menus shows the last temp reading before (thermal?) shutdown, 100 deg C, before reading sensor data.

Don’t Close Your MacBook With a Camera Cover

Apple (via MacRumors, Hacker News):

If you close your Mac notebook with a camera cover installed, you might damage your display because the clearance between the display and keyboard is designed to very tight tolerances. Covering the built-in camera might also interfere with the ambient light sensor and prevent features like automatic brightness and True Tone from working. As an alternative to a camera cover, use the camera indicator light to determine if your camera is active, and decide which apps can use your camera in System Preferences.


The camera is engineered so that it can’t activate without the camera indicator light also turning on. This is how you can tell if your camera is on.

Even assuming there’s no way around that, the light only provides protection when you happen notice it. This will be some time—possibly short or possible very long—after the camera had started recording. If the software simply takes a photo and turns the camera back off, you might not notice the light flash even when sitting at the computer.

If you install a camera cover that is thicker than 0.1mm, remove the camera cover before closing your computer.

I’ve been using a piece of electrical tape, which Wikipedia says is between 0.18mm and 0.25mm thick. I’m not sure what you could use that would be thin enough to leave on.


None of the proposed solutions do anything to actually stop the camera from taking a picture of you. Sure, you’ll see the indicator light up for 3 seconds. But the attacker still got what they needed.

Camera covers have nothing to do with identifying compromise. They are strictly for preventing compromise. This is exactly opposite what a camera indicator light does, and thus the indicator should not be considered a “workaround” for not being able to install a camera cover.


I was very skeptical of the camera covers, but then through conversations with some of my co-workers, I realized that they weren’t being used because people were worried about spies secretly turning on the camera. It was 90% of the time just peace of mind that their camera was actually off, instead of having to find the sometimes hard to see options in video chat programs etc.


Update (2020-07-29): Simone Manganelli:

Even if there were a big omnipresent, easy-to-access button in the menu bar that would turn off the camera, sometimes the OS hangs, or is slow to respond to a button click, and those seconds can be make-it-or-break-it for a huge embarrassment.