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]

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

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