Thank you for thinking about this, @Etresoft. I did not set the Bundle Identifier in this project. It must have been generated by Xcode based on the names I entered into the File > New Project sheets. To find out, I just looked in the Info.plist of the exported notarized .app which exhibits the incorrect behavior. Key CFBundleIdentifier has value com.myCompany.MyApp, as expected. It is not com.myCompany.MyOtherApp. Going further, I searched the project for the string MyOtherApp. As expected, zero occurrences were found. Thinking about this further, maybe I created some kind of developer signing identity, certificate or profile when creating MyOtherApp which is somehow leaking into this new app because I neglected to create the same for it. My experience is limited to signing and, recently of course, notarizing Developer ID apps using the command-line utilities, overwriting any codesigning by Xcode. I have never submitted an app to the Mac App Store. So you seeI have never been motivated to try and understand developer signing identities, certificate, profiles, etc., and that is likely where my problem is. Or a bug in Xcode? I forgot to say that I am using Xcode 12 Beta 5.

Thank you, GabeJones. It worked for me too. After failing with this error as described in the original post 5-10 times today, updating to Xcode 12 Beta 2 solved the problem.

The fix for me was to visit Apple's Developer Downloads page - https://developer.apple.com/download/, download and then install, actually re-install, the beta "Profile". After that reinstall, I did a Check for Update and, voila, I no longer get Unable to check for updates – No available updates found. Please try again later, but instead got the invitation to install Beta 2. Interestingly, today, it is again giving me Unable to check for updates – No available updates found. Please try again later. I see from that Downloads site that Beta 3 is not available yet. But because it is unable to check, I suspect that I will need to do the same trick to get Beta 3. We shall soon find out! By the way, I did report this to Apple, FB7869180. Indications are that this is known, widespread issue that is being worked on.

Well, realizing that I am apparently on my own here, I devised a workaround. Instead of publishing progress values via the non-managed property doneness which I added to Foo, I removed that property and instead publish progress values via an Array property of the "worker" described in my previous post. I suspect the problem is that, as has historically often been the case, NSManagedObject has some special behaviors which cause some customizations by subclasses to fail. In this case, it may be that NSManagedObject has a specialized publishing mechanism which excludes its usage by non-managed properties.

I tried some more ideas, but still not working. First of all, I added a dummy property to the "worker" object which does the work whose progress I need to display. The dummy property is published and observed by the List view, and updated every time any of the doneness values are updated. So now my body() method runs, and I also put the value of this dummy property and the value of foo.doneness in the title of each 'ProgressView'. Result: Now my body() method runs whenever any progress is updated, and the value of the dummy property in each progress view's title updates as expected. But, although the foo.doneness values are definitely being updated (I print the new values to the console in the "worker"), the very same calls, foo.doneness, inside that body() method, as seen in the progress view's title, are stuck at 0.0. In other words, this body() is stuck at the initial value snapshot, definitely not observing any changes. I also tried adding a willSet to Foo.willChange, manually sending objectWillChange as shown below, but this does not help either: @Published var doneness: Double = 0 {     willSet {         objectWillChange.send()     } }

Thank you, Timothy. Done. Please refer to FB7829688.

alarouche, you must (1) install the Xcode 12 beta and then (2) select it. For example, if you have installed Xcode-beta into /Applications, sudo xcode-select -s /Applications/Xcode-beta.app After performing these two steps, then the command shown in the WWDC video xcrun safari-web-extension-converter /path/to/my/extension/folder will work.

For me, using macOS 10.15.6 beta on a MacBook Air, the answer by @teddy06550 was close, but the actual example was simpler. Weird. Teddy's second command failed: Air2:~ jk$ sudo tmutil deletelocalsnapshots 2020-06-15-002518.local Password: 2020-06-15-002518.local is not a valid disk So instead I did what it implied I needed to do: Air2:~ jk$ sudo tmutil deletelocalsnapshots / Deleted 2 Time Machine local snapshots for volume group containing disk '/' com.apple.TimeMachine.2020-06-15-002518.local com.apple.TimeMachine.2020-06-22-183122.local and, voila… Air2:~ jk$ tmutil listlocalsnapshots / Snapshots for volume group containing disk /: Air2:~ jk$ No more local backups. Side note: Before doing this I had 89 GB available, 73.33 GB purgeable and the installer said I had only 16 GB available and needed 34 GB more. After doing this, I have 159 GB available, 73.33 GB purgeable and the installer says I have 86 GB available and it is ready to go. Well, indeed 159-73=86. So it looks like the space used by Time Machine and the space used by "purgeable" are different issues. By the way, think I know how I got so much in Time Machine local backups. During the last few months, I have created a half dozen or so screencast videos using Screenflow, which is an ( excellent) document-based app. Some of them may have been left dangling because I did not want to save them and force quit. That may or may not have made the problem worse. Anyhow, thanks very much to Teddy for the tmutil tip. I think this is a bug – that Time Machine local backups can use such a huge amount of space with absolutely zero visibility. Am I wrong or should I file a bug? Or maybe is this fixed a Big Sur?