I think this should be apple's bug on 10.15.7 I make 3 tests as below: Preconditions: prepare the SampleNetworkExtension.app, put it on the network shared disk, and make a new VM for macos 10.15.7 1.copy SampleNetworkExtension.app to /Applications. run /Applications/SampleNetworkExtension.app, the popup is ok 2.clean up: move /Applications/SampleNetworkExtension.app to Trash and empty Trash, reboot system. copy SampleNetworkExtension.app to /Applications/test.app/Contents/PlugIns. run /Applications/test.app/Contents/PlugIns/SampleNetworkExtension.app, the popup will be null 3.clean up: move /Applications/test.app/Contents/PlugIns/SampleNetworkExtension.app to Trash and empty Trash, reboot system. copy SampleNetworkExtension.app to /Applications/test.app/Contents/PlugIns, and copy it to /Applications also. run /Applications/Contents/PlugIns/SampleNetworkExtension.app, the popup is ok I do the same test on macos 11 or macos 12, that's ok. Maybe apple fixed it on macos 11

hi, eskimo, I also send an email to you, Look forward to your reply！

hello eskimo, Maybe you have misunderstood me, this issue cause by the process which launched by NSTask cann't exit, the NSTask hanged waitpid. I get a Sampling file captured by Activity. it seems caused by os_unfair_lock dead lock too! due to cann't upload file in comment, I put the file to [https://we.tl/t-pLlpar3SfD]