Just to add to what's already been said here: This issue is re-producible when running an affected app on an actual iOS device running iOS 14 Beta 3 (not on the simulator), even with the debugger attached, as follows :- Build & Run an affected app on an actual iOS device running iOS 14 Beta 3. Swipe up from the bottom (or press the home button if your device has one) while the app is in the foreground to send it to the background. That's it: A short moment later, the system kills the app, and Xcode's Console reads: Message from debugger: Terminated due to signal 9 I have also filed FB8214214 for this issue (and included a quick & dirty sample project).

There are tons of issues with the toolbar at the moment. Using the new NSSearchToolbarItem, it will sometimes randomly (for no obvious reason) insert empty space between it & the item before it. Doing anything that causes the toolbar to perform it's layout seems to usually fixes these. The problem is that NSToolbar is not a subclass of NSView, so we can't really force it to perform it's layout without hacks (like toggling it's display mode).

> I'm trying to reproduce this issue with beta 6, but haven't been able to do it. Can anyone confirm that they still see it? I have an extension and an app both using flock to take a lock on a file in a shared container and the app appears to be able to suspend just fine while holding the lock. > >This is using flock(fileHandle.fileDescriptor, LOCK_EX | LOCK_NB) . I can confirm that this is still an issue on beta 6. To reproduce, use the following to get a file descriptor, instead of NSFileHandle. int fd = open([fileUrl path].UTF8String, O_RDWR); and then, the following to acquire a file lock:- int ret = flock(fd, LOCK_SH);

Seeing the same. Wondering if this in Xcode 12 Beta 6 Release Notes (https://developer.apple.com/documentation/xcode-release-notes/xcode-12-beta-release-notes) could be the cause:- A Mac Catalyst app signed to run locally on macOS may fail to run with the Mac (Rosetta) run destination. (64421496) 🤔 UPDATE: It's also in Big Sur Beta 6 Release Notes under Xcode Known Issues :- You're currently unable to launch Mac Catalyst and iOS apps using Xcode. (67356581) So, I guess that settles it for now.

Neither of these identifiers seems to work as of macOS Big Sur Beta 6 Confirmed. Beta 6 has a lot of broken things. 😟