Hi all, as always, apologies if the follow question is answered somewhere that I’ve missed. Should AVAssetDownloadURLSession be functional in the iOS simulator? I’ve only been able to get it to work (as in, not immediately error) on-device. I’m aware that there are some limitations to background sessions in the simulator in general, but I was under the impression that they were at least kinda functional. In the simulator, my URLSession:didBecomeInvalidWithError: delegate method is called immediately with code -1, and a corresponding crash log is generated here: Console > User Reports > nsurlsessiond_[date]-[my machine name].crash Its contents ominously mention: Application Specific Information: BUG IN CLIENT OF LIBDISPATCH: dispatch_barrier_sync called on queue already owned by current thread CoreSimulator 338.16 - Device: iPhone SE - Runtime: iOS 10.2 (14C89) - DeviceType: iPhone SE [snip] Thread 3 Crashed:: Dispatch queue: <AVAssetDownloadSession: 0x7ffa5c40eff0> read/write queue 0 libdispatch.dylib 0x0000000110cf8616 _dispatch_barrier_sync_f_slow + 708 1 com.apple.avfoundation 0x000000010e230d42 -[AVAssetDownloadSession(AVAssetDownloadSession_Local) _transitionToTerminalStatus:error:] + 202 2 com.apple.avfoundation 0x000000010e22f288 __63-[AVAssetDownloadSession initWithAsset:destinationURL:options:]_block_invoke + 1396 3 libdispatch.dylib 0x0000000110cee808 _dispatch_call_block_and_release + 12 4 libdispatch.dylib 0x0000000110d1012e _dispatch_client_callout + 8 5 libdispatch.dylib 0x0000000110cf9766 _dispatch_queue_concurrent_drain + 1543 6 libdispatch.dylib 0x0000000110cf5ca6 _dispatch_queue_invoke + 1125 7 libdispatch.dylib 0x0000000110cf6047 _dispatch_queue_override_invoke + 376 8 libdispatch.dylib 0x0000000110cf79dc _dispatch_root_queue_drain + 506 9 libdispatch.dylib 0x0000000110cf7782 _dispatch_worker_thread3 + 113 10 libsystem_pthread.dylib 0x00000001110bc712 _pthread_wqthread + 1299 11 libsystem_pthread.dylib 0x00000001110bc1ed start_wqthread + 13 I get a similar crash exercising the class via a Playground (my initial intent), an iOS unit test target, or an actual skeleton iPhone app. Is this expected? Happy to file a bug for this if it should be working — this seems like a fun class to be able to play with in a Playground, in particular. Cheers, Peter _______________________________________________ Do not post admin requests to the list. They will be ignored. Macnetworkprog mailing list (Macnetworkprog@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/macnetworkprog/site_archiver%40lists... This email sent to site_archiver@lists.apple.com